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venv
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.idea
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.vscode
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Untitled.ipynb
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# 100 numpy exercises with hint
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This is a collection of exercises that have been collected in the numpy mailing
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list, on stack overflow and in the numpy documentation. I've also created some
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to reach the 100 limit. The goal of this collection is to offer a quick
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reference for both old and new users but also to provide a set of exercises for
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those who teach.
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If you find an error or think you've a better way to solve some of them, feel
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free to open an issue at <https://github.com/rougier/numpy-100>
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#### 1. Import the numpy package under the name `np` (★☆☆)
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(**hint**: import … as …)
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#### 2. Print the numpy version and the configuration (★☆☆)
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(**hint**: np.\_\_version\_\_, np.show\_config)
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#### 3. Create a null vector of size 10 (★☆☆)
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(**hint**: np.zeros)
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#### 4. How to find the memory size of any array (★☆☆)
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(**hint**: size, itemsize)
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#### 5. How to get the documentation of the numpy add function from the command line? (★☆☆)
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(**hint**: np.info)
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#### 6. Create a null vector of size 10 but the fifth value which is 1 (★☆☆)
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(**hint**: array\[4\])
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#### 7. Create a vector with values ranging from 10 to 49 (★☆☆)
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(**hint**: np.arange)
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#### 8. Reverse a vector (first element becomes last) (★☆☆)
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(**hint**: array\[::-1\])
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#### 9. Create a 3x3 matrix with values ranging from 0 to 8 (★☆☆)
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(**hint**: reshape)
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#### 10. Find indices of non-zero elements from \[1,2,0,0,4,0\] (★☆☆)
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(**hint**: np.nonzero)
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#### 11. Create a 3x3 identity matrix (★☆☆)
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(**hint**: np.eye)
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#### 12. Create a 3x3x3 array with random values (★☆☆)
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(**hint**: np.random.random)
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#### 13. Create a 10x10 array with random values and find the minimum and maximum values (★☆☆)
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(**hint**: min, max)
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#### 14. Create a random vector of size 30 and find the mean value (★☆☆)
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(**hint**: mean)
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#### 15. Create a 2d array with 1 on the border and 0 inside (★☆☆)
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(**hint**: array\[1:-1, 1:-1\])
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#### 16. How to add a border (filled with 0's) around an existing array? (★☆☆)
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(**hint**: np.pad)
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#### 17. What is the result of the following expression? (★☆☆)
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(**hint**: NaN = not a number, inf = infinity)
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```python
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0 * np.nan
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np.nan == np.nan
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np.inf > np.nan
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np.nan - np.nan
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np.nan in set([np.nan])
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0.3 == 3 * 0.1
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```
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#### 18. Create a 5x5 matrix with values 1,2,3,4 just below the diagonal (★☆☆)
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(**hint**: np.diag)
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#### 19. Create a 8x8 matrix and fill it with a checkerboard pattern (★☆☆)
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(**hint**: array\[::2\])
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#### 20. Consider a (6,7,8) shape array, what is the index (x,y,z) of the 100th element?
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(**hint**: np.unravel\_index)
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#### 21. Create a checkerboard 8x8 matrix using the tile function (★☆☆)
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(**hint**: np.tile)
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#### 22. Normalize a 5x5 random matrix (★☆☆)
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(**hint**: (x - mean) / std)
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#### 23. Create a custom dtype that describes a color as four unsigned bytes (RGBA) (★☆☆)
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(**hint**: np.dtype)
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#### 24. Multiply a 5x3 matrix by a 3x2 matrix (real matrix product) (★☆☆)
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(**hint**: np.dot | @)
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#### 25. Given a 1D array, negate all elements which are between 3 and 8, in place. (★☆☆)
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(**hint**: >, <=)
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#### 26. What is the output of the following script? (★☆☆)
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(**hint**: np.sum)
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```python
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# Author: Jake VanderPlas
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print(sum(range(5),-1))
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from numpy import *
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print(sum(range(5),-1))
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```
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#### 27. Consider an integer vector Z, which of these expressions are legal? (★☆☆)
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```python
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Z**Z
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2 << Z >> 2
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Z <- Z
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1j*Z
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Z/1/1
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Z<Z>Z
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```
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#### 28. What are the result of the following expressions?
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```python
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np.array(0) / np.array(0)
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np.array(0) // np.array(0)
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np.array([np.nan]).astype(int).astype(float)
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```
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#### 29. How to round away from zero a float array ? (★☆☆)
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(**hint**: np.uniform, np.copysign, np.ceil, np.abs)
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#### 30. How to find common values between two arrays? (★☆☆)
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(**hint**: np.intersect1d)
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#### 31. How to ignore all numpy warnings (not recommended)? (★☆☆)
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(**hint**: np.seterr, np.errstate)
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#### 32. Is the following expressions true? (★☆☆)
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(**hint**: imaginary number)
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```python
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np.sqrt(-1) == np.emath.sqrt(-1)
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```
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#### 33. How to get the dates of yesterday, today and tomorrow? (★☆☆)
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(**hint**: np.datetime64, np.timedelta64)
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#### 34. How to get all the dates corresponding to the month of July 2016? (★★☆)
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(**hint**: np.arange(dtype=datetime64\['D'\]))
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#### 35. How to compute ((A+B)\*(-A/2)) in place (without copy)? (★★☆)
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(**hint**: np.add(out=), np.negative(out=), np.multiply(out=), np.divide(out=))
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#### 36. Extract the integer part of a random array using 5 different methods (★★☆)
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(**hint**: %, np.floor, np.ceil, astype, np.trunc)
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#### 37. Create a 5x5 matrix with row values ranging from 0 to 4 (★★☆)
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(**hint**: np.arange)
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#### 38. Consider a generator function that generates 10 integers and use it to build an array (★☆☆)
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(**hint**: np.fromiter)
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#### 39. Create a vector of size 10 with values ranging from 0 to 1, both excluded (★★☆)
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(**hint**: np.linspace)
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#### 40. Create a random vector of size 10 and sort it (★★☆)
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(**hint**: sort)
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#### 41. How to sum a small array faster than np.sum? (★★☆)
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(**hint**: np.add.reduce)
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#### 42. Consider two random array A and B, check if they are equal (★★☆)
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(**hint**: np.allclose, np.array\_equal)
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#### 43. Make an array immutable (read-only) (★★☆)
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(**hint**: flags.writeable)
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#### 44. Consider a random 10x2 matrix representing cartesian coordinates, convert them to polar coordinates (★★☆)
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(**hint**: np.sqrt, np.arctan2)
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#### 45. Create random vector of size 10 and replace the maximum value by 0 (★★☆)
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(**hint**: argmax)
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#### 46. Create a structured array with `x` and `y` coordinates covering the \[0,1\]x\[0,1\] area (★★☆)
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(**hint**: np.meshgrid)
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#### 47. Given two arrays, X and Y, construct the Cauchy matrix C (Cij =1/(xi - yj))
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##### (hint: np.subtract.outer)
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#### 48. Print the minimum and maximum representable value for each numpy scalar type (★★☆)
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(**hint**: np.iinfo, np.finfo, eps)
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#### 49. How to print all the values of an array? (★★☆)
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(**hint**: np.set\_printoptions)
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#### 50. How to find the closest value (to a given scalar) in a vector? (★★☆)
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(**hint**: argmin)
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#### 51. Create a structured array representing a position (x,y) and a color (r,g,b) (★★☆)
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(**hint**: dtype)
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#### 52. Consider a random vector with shape (100,2) representing coordinates, find point by point distances (★★☆)
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(**hint**: np.atleast\_2d, T, np.sqrt)
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#### 53. How to convert a float (32 bits) array into an integer (32 bits) in place?
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(**hint**: astype(copy=False))
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#### 54. How to read the following file? (★★☆)
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(**hint**: np.genfromtxt)
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```
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1, 2, 3, 4, 5
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6, , , 7, 8
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, , 9,10,11
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```
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#### 55. What is the equivalent of enumerate for numpy arrays? (★★☆)
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(**hint**: np.ndenumerate, np.ndindex)
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#### 56. Generate a generic 2D Gaussian-like array (★★☆)
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(**hint**: np.meshgrid, np.exp)
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#### 57. How to randomly place p elements in a 2D array? (★★☆)
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(**hint**: np.put, np.random.choice)
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#### 58. Subtract the mean of each row of a matrix (★★☆)
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(**hint**: mean(axis=,keepdims=))
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#### 59. How to sort an array by the nth column? (★★☆)
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(**hint**: argsort)
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#### 60. How to tell if a given 2D array has null columns? (★★☆)
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(**hint**: any, ~)
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#### 61. Find the nearest value from a given value in an array (★★☆)
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(**hint**: np.abs, argmin, flat)
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#### 62. Considering two arrays with shape (1,3) and (3,1), how to compute their sum using an iterator? (★★☆)
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(**hint**: np.nditer)
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#### 63. Create an array class that has a name attribute (★★☆)
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(**hint**: class method)
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#### 64. Consider a given vector, how to add 1 to each element indexed by a second vector (be careful with repeated indices)? (★★★)
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(**hint**: np.bincount | np.add.at)
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#### 65. How to accumulate elements of a vector (X) to an array (F) based on an index list (I)? (★★★)
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(**hint**: np.bincount)
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#### 66. Considering a (w,h,3) image of (dtype=ubyte), compute the number of unique colors (★★★)
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(**hint**: np.unique)
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#### 67. Considering a four dimensions array, how to get sum over the last two axis at once? (★★★)
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(**hint**: sum(axis=(-2,-1)))
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#### 68. Considering a one-dimensional vector D, how to compute means of subsets of D using a vector S of same size describing subset indices? (★★★)
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(**hint**: np.bincount)
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#### 69. How to get the diagonal of a dot product? (★★★)
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(**hint**: np.diag)
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#### 70. Consider the vector \[1, 2, 3, 4, 5\], how to build a new vector with 3 consecutive zeros interleaved between each value? (★★★)
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(**hint**: array\[::4\])
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#### 71. Consider an array of dimension (5,5,3), how to mulitply it by an array with dimensions (5,5)? (★★★)
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(**hint**: array\[:, :, None\])
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#### 72. How to swap two rows of an array? (★★★)
|
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|
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(**hint**: array\[\[\]\] = array\[\[\]\])
|
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#### 73. Consider a set of 10 triplets describing 10 triangles (with shared vertices), find the set of unique line segments composing all the triangles (★★★)
|
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|
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(**hint**: repeat, np.roll, np.sort, view, np.unique)
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#### 74. Given an array C that is a bincount, how to produce an array A such that np.bincount(A) == C? (★★★)
|
||||
|
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(**hint**: np.repeat)
|
||||
|
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|
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#### 75. How to compute averages using a sliding window over an array? (★★★)
|
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|
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(**hint**: np.cumsum)
|
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|
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#### 76. Consider a one-dimensional array Z, build a two-dimensional array whose first row is (Z\[0\],Z\[1\],Z\[2\]) and each subsequent row is shifted by 1 (last row should be (Z\[-3\],Z\[-2\],Z\[-1\]) (★★★)
|
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|
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(**hint**: from numpy.lib import stride\_tricks)
|
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|
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|
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#### 77. How to negate a boolean, or to change the sign of a float inplace? (★★★)
|
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|
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(**hint**: np.logical_not, np.negative)
|
||||
|
||||
|
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|
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#### 78. Consider 2 sets of points P0,P1 describing lines (2d) and a point p, how to compute distance from p to each line i (P0\[i\],P1\[i\])? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 79. Consider 2 sets of points P0,P1 describing lines (2d) and a set of points P, how to compute distance from each point j (P\[j\]) to each line i (P0\[i\],P1\[i\])? (★★★)
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||||
|
||||
|
||||
|
||||
#### 80. Consider an arbitrary array, write a function that extract a subpart with a fixed shape and centered on a given element (pad with a `fill` value when necessary) (★★★)
|
||||
|
||||
(**hint**: minimum, maximum)
|
||||
|
||||
|
||||
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#### 81. Consider an array Z = \[1,2,3,4,5,6,7,8,9,10,11,12,13,14\], how to generate an array R = \[\[1,2,3,4\], \[2,3,4,5\], \[3,4,5,6\], ..., \[11,12,13,14\]\]? (★★★)
|
||||
|
||||
(**hint**: stride\_tricks.as\_strided)
|
||||
|
||||
|
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#### 82. Compute a matrix rank (★★★)
|
||||
|
||||
(**hint**: np.linalg.svd)
|
||||
|
||||
|
||||
|
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#### 83. How to find the most frequent value in an array?
|
||||
|
||||
(**hint**: np.bincount, argmax)
|
||||
|
||||
|
||||
|
||||
#### 84. Extract all the contiguous 3x3 blocks from a random 10x10 matrix (★★★)
|
||||
|
||||
(**hint**: stride\_tricks.as\_strided)
|
||||
|
||||
|
||||
|
||||
#### 85. Create a 2D array subclass such that Z\[i,j\] == Z\[j,i\] (★★★)
|
||||
|
||||
(**hint**: class method)
|
||||
|
||||
|
||||
|
||||
#### 86. Consider a set of p matrices wich shape (n,n) and a set of p vectors with shape (n,1). How to compute the sum of of the p matrix products at once? (result has shape (n,1)) (★★★)
|
||||
|
||||
(**hint**: np.tensordot)
|
||||
|
||||
|
||||
|
||||
#### 87. Consider a 16x16 array, how to get the block-sum (block size is 4x4)? (★★★)
|
||||
|
||||
(**hint**: np.add.reduceat)
|
||||
|
||||
|
||||
|
||||
#### 88. How to implement the Game of Life using numpy arrays? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 89. How to get the n largest values of an array (★★★)
|
||||
|
||||
(**hint**: np.argsort | np.argpartition)
|
||||
|
||||
|
||||
|
||||
#### 90. Given an arbitrary number of vectors, build the cartesian product (every combinations of every item) (★★★)
|
||||
|
||||
(**hint**: np.indices)
|
||||
|
||||
|
||||
|
||||
#### 91. How to create a record array from a regular array? (★★★)
|
||||
|
||||
(**hint**: np.core.records.fromarrays)
|
||||
|
||||
|
||||
|
||||
#### 92. Consider a large vector Z, compute Z to the power of 3 using 3 different methods (★★★)
|
||||
|
||||
(**hint**: np.power, \*, np.einsum)
|
||||
|
||||
|
||||
|
||||
#### 93. Consider two arrays A and B of shape (8,3) and (2,2). How to find rows of A that contain elements of each row of B regardless of the order of the elements in B? (★★★)
|
||||
|
||||
(**hint**: np.where)
|
||||
|
||||
|
||||
|
||||
#### 94. Considering a 10x3 matrix, extract rows with unequal values (e.g. \[2,2,3\]) (★★★)
|
||||
|
||||
|
||||
|
||||
#### 95. Convert a vector of ints into a matrix binary representation (★★★)
|
||||
|
||||
(**hint**: np.unpackbits)
|
||||
|
||||
|
||||
|
||||
#### 96. Given a two dimensional array, how to extract unique rows? (★★★)
|
||||
|
||||
(**hint**: np.ascontiguousarray | np.unique)
|
||||
|
||||
|
||||
|
||||
#### 97. Considering 2 vectors A & B, write the einsum equivalent of inner, outer, sum, and mul function (★★★)
|
||||
|
||||
(**hint**: np.einsum)
|
||||
|
||||
|
||||
|
||||
#### 98. Considering a path described by two vectors (X,Y), how to sample it using equidistant samples (★★★)?
|
||||
|
||||
(**hint**: np.cumsum, np.interp)
|
||||
|
||||
|
||||
|
||||
#### 99. Given an integer n and a 2D array X, select from X the rows which can be interpreted as draws from a multinomial distribution with n degrees, i.e., the rows which only contain integers and which sum to n. (★★★)
|
||||
|
||||
(**hint**: np.logical\_and.reduce, np.mod)
|
||||
|
||||
|
||||
|
||||
#### 100. Compute bootstrapped 95% confidence intervals for the mean of a 1D array X (i.e., resample the elements of an array with replacement N times, compute the mean of each sample, and then compute percentiles over the means). (★★★)
|
||||
|
||||
(**hint**: np.percentile)
|
||||
|
||||
@ -7,5 +7,9 @@ This is a collection of numpy exercises from numpy mailing list, stack overflow,
|
||||
→ [Test them on Binder](http://mybinder.org:/repo/rougier/numpy-100/notebooks/100_Numpy_exercises.ipynb)
|
||||
→ [Read them on GitHub](100_Numpy_exercises.md)
|
||||
|
||||
Note: markdown and ipython notebook are created programmatically from the dictionary in `data_source.py`.
|
||||
To modify the content of these files, chance the text in `data_source.py` and then re-generate them via the
|
||||
method into the `generators.py` module.
|
||||
|
||||
This work is licensed under the MIT license.
|
||||
[](https://zenodo.org/badge/latestdoi/10173/rougier/numpy-100)
|
||||
|
||||
14
TODO.txt
14
TODO.txt
@ -1,14 +0,0 @@
|
||||
v get a single python file with all questions, hints and answers in a single dictionary.
|
||||
v implement 3 functions: question, hint and solution, printing the required question, hint and solution in an `initialise.py` file.
|
||||
v initialise must also have a pick() function for a random game.
|
||||
+ produce one jupyter with all the questions, the initialise.py in the first cell creating the full notebook: numpy_100_consecutive.ipynb
|
||||
+ produce one jupyter notebook with the random game: numpy_100_random.ipynb.
|
||||
+ produce the method to create the md files (questions, questions with hints, questions with solutions, questions with hints and solution)
|
||||
+ add to this method the a cli interface for quick manipulation.
|
||||
+ produce and leave the files created with the cli.
|
||||
+ cleanup. Erase all the other notebook but the two new 2 jupyter notebooks - numpy_100_consecutive.ipynb numpy_100_random.ipynb.
|
||||
+ change the instructions in the readme to create the markdown files with hints with hints and answers and with only questions.
|
||||
+ send PR.
|
||||
|
||||
Utilities:
|
||||
https://stackoverflow.com/questions/13614783/programmatically-add-cells-to-an-ipython-notebook-for-report-generation
|
||||
@ -1,5 +1,28 @@
|
||||
HEADER = """
|
||||
# 100 numpy exercises
|
||||
|
||||
qha = {
|
||||
This is a collection of exercises that have been collected in the numpy mailing list, on stack overflow
|
||||
and in the numpy documentation. The goal of this collection is to offer a quick reference for both old
|
||||
and new users but also to provide a set of exercises for those who teach.
|
||||
|
||||
|
||||
If you find an error or think you've a better way to solve some of them, feel
|
||||
free to open an issue at <https://github.com/rougier/numpy-100>
|
||||
"""
|
||||
|
||||
SUB_HEADER = "File automatically generated. See the documentation to update questions/answers/hints" \
|
||||
" programmatically."
|
||||
|
||||
JUPYTER_INSTRUCTIONS = "Run the `initialize.py` module, then for each question you can query the " \
|
||||
"answer or an hint with `hint(n)` or `answer(n)` for `n` question number."
|
||||
|
||||
|
||||
JUPYTER_INSTRUCTIONS_RAND = "Run the `initialize.py` module, then call a random question with `pick()`" \
|
||||
"an hint towards its solution with `hint(n)` and the answer with `answer(n)`," \
|
||||
"where n is the number of the picked question."
|
||||
|
||||
|
||||
QHA = {
|
||||
"q1": "Import the numpy package under the name `np` (★☆☆)",
|
||||
"h1": "hint: import … as ",
|
||||
"a1":
|
||||
@ -116,16 +139,16 @@ Z = np.ones((5,5))
|
||||
Z = np.pad(Z, pad_width=1, mode='constant', constant_values=0)
|
||||
print(Z)
|
||||
""",
|
||||
"q17": """
|
||||
What is the result of the following expression? (★☆☆)"
|
||||
"q17": """\
|
||||
What is the result of the following expression? (★☆☆)
|
||||
```python
|
||||
0 * np.nan
|
||||
np.nan == np.nan
|
||||
np.inf > np.nan
|
||||
np.nan - np.nan
|
||||
np.nan in set([np.nan])
|
||||
# 0.3 == 3 * 0.1
|
||||
# ```""",
|
||||
0.3 == 3 * 0.1
|
||||
```""",
|
||||
"h17": "hint: NaN = not a number, inf = infinity",
|
||||
"a17":
|
||||
"""
|
||||
@ -204,7 +227,7 @@ Z[(3 < Z) & (Z <= 8)] *= -1
|
||||
print(Z)
|
||||
|
||||
""",
|
||||
"q26": """
|
||||
"q26": """\
|
||||
What is the output of the following script? (★☆☆)
|
||||
```python
|
||||
# Author: Jake VanderPlas
|
||||
@ -223,7 +246,7 @@ print(sum(range(5),-1))
|
||||
from numpy import *
|
||||
print(sum(range(5),-1))
|
||||
""",
|
||||
"q27": """
|
||||
"q27": """\
|
||||
Consider an integer vector Z, which of these expressions are legal? (★☆☆)
|
||||
```python
|
||||
Z**Z
|
||||
@ -243,7 +266,7 @@ Z <- Z
|
||||
Z/1/1
|
||||
Z<Z>Z
|
||||
""",
|
||||
"q28": """
|
||||
"q28": """\
|
||||
What are the result of the following expressions?
|
||||
```python
|
||||
np.array(0) / np.array(0)
|
||||
@ -291,7 +314,7 @@ _ = np.seterr(**defaults)
|
||||
nz = np.nonzero([1,2,0,0,4,0])
|
||||
print(nz)
|
||||
""",
|
||||
"q32": """
|
||||
"q32": """\
|
||||
Is the following expressions true? (★☆☆)
|
||||
```python
|
||||
np.sqrt(-1) == np.emath.sqrt(-1)
|
||||
@ -511,7 +534,7 @@ Z = np.arange(10, dtype=np.float32)
|
||||
Z = Z.astype(np.int32, copy=False)
|
||||
print(Z)
|
||||
""",
|
||||
"q54": """
|
||||
"q54": """\
|
||||
How to read the following file? (★★☆)
|
||||
```
|
||||
1, 2, 3, 4, 5
|
||||
97
generators.py
Normal file
97
generators.py
Normal file
@ -0,0 +1,97 @@
|
||||
import os
|
||||
import nbformat as nbf
|
||||
import mdutils
|
||||
|
||||
import data_source as ds
|
||||
|
||||
|
||||
def create_jupyter_notebook(destination_filename='numpy_100.ipynb'):
|
||||
""" Programmatically create jupyter notebook with the questions (and hints and solutions if required)
|
||||
saved under data_source.py """
|
||||
|
||||
# Create cells sequence
|
||||
nb = nbf.v4.new_notebook()
|
||||
|
||||
nb['cells'] = []
|
||||
|
||||
# - Add header:
|
||||
nb['cells'].append(nbf.v4.new_markdown_cell(ds.HEADER))
|
||||
nb['cells'].append(nbf.v4.new_markdown_cell(ds.SUB_HEADER))
|
||||
nb['cells'].append(nbf.v4.new_markdown_cell(ds.JUPYTER_INSTRUCTIONS))
|
||||
|
||||
# - Add initialisation
|
||||
nb['cells'].append(nbf.v4.new_code_cell('%run initialise.py'))
|
||||
|
||||
# - Add questions and empty spaces for answers
|
||||
for n in range(1, 101):
|
||||
nb['cells'].append(nbf.v4.new_markdown_cell(f'#### {n}. ' + ds.QHA[f'q{n}']))
|
||||
nb['cells'].append(nbf.v4.new_code_cell(""))
|
||||
|
||||
# Delete file if one with the same name is found
|
||||
if os.path.exists(destination_filename):
|
||||
os.remove(destination_filename)
|
||||
|
||||
# Write sequence to file
|
||||
nbf.write(nb, destination_filename)
|
||||
|
||||
|
||||
def create_jupyter_notebook_random_question(destination_filename='numpy_100_random.ipynb'):
|
||||
""" Programmatically create jupyter notebook with the questions (and hints and solutions if required)
|
||||
saved under data_source.py """
|
||||
|
||||
# Create cells sequence
|
||||
nb = nbf.v4.new_notebook()
|
||||
|
||||
nb['cells'] = []
|
||||
|
||||
# - Add header:
|
||||
nb['cells'].append(nbf.v4.new_markdown_cell(ds.HEADER))
|
||||
nb['cells'].append(nbf.v4.new_markdown_cell(ds.SUB_HEADER))
|
||||
nb['cells'].append(nbf.v4.new_markdown_cell(ds.JUPYTER_INSTRUCTIONS_RAND))
|
||||
|
||||
# - Add initialisation
|
||||
nb['cells'].append(nbf.v4.new_code_cell('%run initialise.py'))
|
||||
nb['cells'].append(nbf.v4.new_code_cell("pick()"))
|
||||
|
||||
# Delete file if one with the same name is found
|
||||
if os.path.exists(destination_filename):
|
||||
os.remove(destination_filename)
|
||||
|
||||
# Write sequence to file
|
||||
nbf.write(nb, destination_filename)
|
||||
|
||||
|
||||
def create_markdown(destination_filename='numpy_100', with_hints=False, with_solutions=False):
|
||||
# Create file name
|
||||
if with_hints:
|
||||
destination_filename += '_with_hints'
|
||||
if with_solutions:
|
||||
destination_filename += '_with_solutions'
|
||||
|
||||
# Initialise file
|
||||
mdfile = mdutils.MdUtils(file_name=destination_filename)
|
||||
|
||||
# Add headers
|
||||
mdfile.write(ds.HEADER)
|
||||
mdfile.write(ds.SUB_HEADER)
|
||||
|
||||
# Add questions (and hint or answers if required)
|
||||
for n in range(1, 101):
|
||||
mdfile.new_header(title=f"{n}. {ds.QHA[f'q{n}']}", level=4)
|
||||
if with_hints:
|
||||
mdfile.write(f"`{ds.QHA[f'h{n}']}`")
|
||||
if with_solutions:
|
||||
mdfile.insert_code(ds.QHA[f'a{n}'], language='python')
|
||||
|
||||
# Delete file if one with the same name is found
|
||||
if os.path.exists(destination_filename):
|
||||
os.remove(destination_filename)
|
||||
|
||||
# Write sequence to file
|
||||
mdfile.create_md_file()
|
||||
|
||||
|
||||
def create_rst(destination_filename, with_ints=False, with_answers=False):
|
||||
# TODO: use rstdoc python library.
|
||||
# also see possible integrations with https://github.com/rougier/numpy-100/pull/38
|
||||
pass
|
||||
@ -1,18 +1,18 @@
|
||||
import numpy as np
|
||||
|
||||
from questsions_dict import qha
|
||||
import data_source as ds
|
||||
|
||||
|
||||
def question(n):
|
||||
print(f'{n}. ' + qha[f'q{n}'])
|
||||
print(f'{n}. ' + ds.QHA[f'q{n}'])
|
||||
|
||||
|
||||
def hint(n):
|
||||
print(qha[f'h{n}'])
|
||||
print(ds.QHA[f'h{n}'])
|
||||
|
||||
|
||||
def answer(n):
|
||||
print(qha[f'a{n}'])
|
||||
print(ds.QHA[f'a{n}'])
|
||||
|
||||
|
||||
def pick():
|
||||
File diff suppressed because it is too large
Load Diff
@ -1,82 +1,50 @@
|
||||
|
||||
|
||||
|
||||
|
||||
# 100 numpy exercises
|
||||
|
||||
This is a collection of exercises that have been collected in the numpy mailing
|
||||
list, on stack overflow and in the numpy documentation. I've also created some
|
||||
to reach the 100 limit. The goal of this collection is to offer a quick
|
||||
reference for both old and new users but also to provide a set of exercises for
|
||||
those who teach.
|
||||
This is a collection of exercises that have been collected in the numpy mailing list, on stack overflow
|
||||
and in the numpy documentation. The goal of this collection is to offer a quick reference for both old
|
||||
and new users but also to provide a set of exercises for those who teach.
|
||||
|
||||
If you find an error or think you've a better way to solve some of them, feel
|
||||
|
||||
If you find an error or think you've a better way to solve some of them, feel
|
||||
free to open an issue at <https://github.com/rougier/numpy-100>
|
||||
|
||||
File automatically generated. See the documentation to update questions/answers/hints programmatically.
|
||||
#### 1. Import the numpy package under the name `np` (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 2. Print the numpy version and the configuration (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 3. Create a null vector of size 10 (★☆☆)
|
||||
|
||||
#### 4. How to find the memory size of any array (★☆☆)
|
||||
|
||||
#### 5. How to get the documentation of the numpy add function from the command line? (★☆☆)
|
||||
|
||||
#### 4. How to find the memory size of any array (★☆☆)
|
||||
#### 6. Create a null vector of size 10 but the fifth value which is 1 (★☆☆)
|
||||
|
||||
#### 7. Create a vector with values ranging from 10 to 49 (★☆☆)
|
||||
|
||||
#### 8. Reverse a vector (first element becomes last) (★☆☆)
|
||||
|
||||
#### 5. How to get the documentation of the numpy add function from the command line? (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 6. Create a null vector of size 10 but the fifth value which is 1 (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 7. Create a vector with values ranging from 10 to 49 (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 8. Reverse a vector (first element becomes last) (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 9. Create a 3x3 matrix with values ranging from 0 to 8 (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 10. Find indices of non-zero elements from \[1,2,0,0,4,0\] (★☆☆)
|
||||
|
||||
#### 9. Create a 3x3 matrix with values ranging from 0 to 8 (★☆☆)
|
||||
|
||||
#### 10. Find indices of non-zero elements from [1,2,0,0,4,0] (★☆☆)
|
||||
|
||||
#### 11. Create a 3x3 identity matrix (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 12. Create a 3x3x3 array with random values (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 13. Create a 10x10 array with random values and find the minimum and maximum values (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 14. Create a random vector of size 30 and find the mean value (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 15. Create a 2d array with 1 on the border and 0 inside (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 16. How to add a border (filled with 0's) around an existing array? (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 17. What is the result of the following expression? (★☆☆)
|
||||
|
||||
|
||||
```python
|
||||
0 * np.nan
|
||||
np.nan == np.nan
|
||||
@ -88,39 +56,21 @@ np.nan in set([np.nan])
|
||||
|
||||
#### 18. Create a 5x5 matrix with values 1,2,3,4 just below the diagonal (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 19. Create a 8x8 matrix and fill it with a checkerboard pattern (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 20. Consider a (6,7,8) shape array, what is the index (x,y,z) of the 100th element?
|
||||
|
||||
|
||||
|
||||
#### 21. Create a checkerboard 8x8 matrix using the tile function (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 22. Normalize a 5x5 random matrix (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 23. Create a custom dtype that describes a color as four unsigned bytes (RGBA) (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 24. Multiply a 5x3 matrix by a 3x2 matrix (real matrix product) (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 25. Given a 1D array, negate all elements which are between 3 and 8, in place. (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 26. What is the output of the following script? (★☆☆)
|
||||
|
||||
|
||||
```python
|
||||
# Author: Jake VanderPlas
|
||||
|
||||
@ -129,9 +79,8 @@ from numpy import *
|
||||
print(sum(range(5),-1))
|
||||
```
|
||||
|
||||
|
||||
#### 27. Consider an integer vector Z, which of these expressions are legal? (★☆☆)
|
||||
|
||||
|
||||
```python
|
||||
Z**Z
|
||||
2 << Z >> 2
|
||||
@ -142,305 +91,163 @@ Z<Z>Z
|
||||
```
|
||||
|
||||
#### 28. What are the result of the following expressions?
|
||||
|
||||
|
||||
```python
|
||||
np.array(0) / np.array(0)
|
||||
np.array(0) // np.array(0)
|
||||
np.array([np.nan]).astype(int).astype(float)
|
||||
```
|
||||
|
||||
|
||||
#### 29. How to round away from zero a float array ? (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 30. How to find common values between two arrays? (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 31. How to ignore all numpy warnings (not recommended)? (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 32. Is the following expressions true? (★☆☆)
|
||||
|
||||
|
||||
```python
|
||||
np.sqrt(-1) == np.emath.sqrt(-1)
|
||||
```
|
||||
|
||||
|
||||
#### 33. How to get the dates of yesterday, today and tomorrow? (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 34. How to get all the dates corresponding to the month of July 2016? (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 35. How to compute ((A+B)\*(-A/2)) in place (without copy)? (★★☆)
|
||||
|
||||
|
||||
#### 35. How to compute ((A+B)*(-A/2)) in place (without copy)? (★★☆)
|
||||
|
||||
#### 36. Extract the integer part of a random array using 5 different methods (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 37. Create a 5x5 matrix with row values ranging from 0 to 4 (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 38. Consider a generator function that generates 10 integers and use it to build an array (★☆☆)
|
||||
|
||||
|
||||
|
||||
#### 39. Create a vector of size 10 with values ranging from 0 to 1, both excluded (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 40. Create a random vector of size 10 and sort it (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 41. How to sum a small array faster than np.sum? (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 42. Consider two random array A and B, check if they are equal (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 43. Make an array immutable (read-only) (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 44. Consider a random 10x2 matrix representing cartesian coordinates, convert them to polar coordinates (★★☆)
|
||||
|
||||
#### 45. Create random vector of size 10 and replace the maximum value by 0 (★★☆)
|
||||
|
||||
#### 46. Create a structured array with `x` and `y` coordinates covering the [0,1]x[0,1] area (★★☆)
|
||||
|
||||
#### 45. Create a random vector of size 10 and replace the maximum value by 0 (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 46. Create a structured array with `x` and `y` coordinates covering the \[0,1\]x\[0,1\] area (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 47. Given two arrays, X and Y, construct the Cauchy matrix C (Cij =1/(xi - yj))
|
||||
|
||||
|
||||
#### 47. Given two arrays, X and Y, construct the Cauchy matrix C (Cij =1/(xi - yj))
|
||||
|
||||
#### 48. Print the minimum and maximum representable value for each numpy scalar type (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 49. How to print all the values of an array? (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 50. How to find the closest value (to a given scalar) in a vector? (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 51. Create a structured array representing a position (x,y) and a color (r,g,b) (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 52. Consider a random vector with shape (100,2) representing coordinates, find point by point distances (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 53. How to convert a float (32 bits) array into an integer (32 bits) in place?
|
||||
|
||||
|
||||
|
||||
#### 54. How to read the following file? (★★☆)
|
||||
|
||||
|
||||
```
|
||||
1, 2, 3, 4, 5
|
||||
6, , , 7, 8
|
||||
, , 9,10,11
|
||||
```
|
||||
|
||||
|
||||
#### 55. What is the equivalent of enumerate for numpy arrays? (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 56. Generate a generic 2D Gaussian-like array (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 57. How to randomly place p elements in a 2D array? (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 58. Subtract the mean of each row of a matrix (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 59. How to sort an array by the nth column? (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 60. How to tell if a given 2D array has null columns? (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 61. Find the nearest value from a given value in an array (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 62. Considering two arrays with shape (1,3) and (3,1), how to compute their sum using an iterator? (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 63. Create an array class that has a name attribute (★★☆)
|
||||
|
||||
|
||||
|
||||
#### 64. Consider a given vector, how to add 1 to each element indexed by a second vector (be careful with repeated indices)? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 65. How to accumulate elements of a vector (X) to an array (F) based on an index list (I)? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 66. Considering a (w,h,3) image of (dtype=ubyte), compute the number of unique colors (★★★)
|
||||
|
||||
|
||||
|
||||
#### 67. Considering a four dimensions array, how to get sum over the last two axis at once? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 68. Considering a one-dimensional vector D, how to compute means of subsets of D using a vector S of same size describing subset indices? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 69. How to get the diagonal of a dot product? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 70. Consider the vector \[1, 2, 3, 4, 5\], how to build a new vector with 3 consecutive zeros interleaved between each value? (★★★)
|
||||
|
||||
|
||||
#### 70. Consider the vector [1, 2, 3, 4, 5], how to build a new vector with 3 consecutive zeros interleaved between each value? (★★★)
|
||||
|
||||
#### 71. Consider an array of dimension (5,5,3), how to mulitply it by an array with dimensions (5,5)? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 72. How to swap two rows of an array? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 73. Consider a set of 10 triplets describing 10 triangles (with shared vertices), find the set of unique line segments composing all the triangles (★★★)
|
||||
|
||||
|
||||
|
||||
#### 74. Given an array C that is a bincount, how to produce an array A such that np.bincount(A) == C? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 75. How to compute averages using a sliding window over an array? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 76. Consider a one-dimensional array Z, build a two-dimensional array whose first row is (Z\[0\],Z\[1\],Z\[2\]) and each subsequent row is shifted by 1 (last row should be (Z\[-3\],Z\[-2\],Z\[-1\]) (★★★)
|
||||
|
||||
|
||||
#### 76. Consider a one-dimensional array Z, build a two-dimensional array whose first row is (Z[0],Z[1],Z[2]) and each subsequent row is shifted by 1 (last row should be (Z[-3],Z[-2],Z[-1]) (★★★)
|
||||
|
||||
#### 77. How to negate a boolean, or to change the sign of a float inplace? (★★★)
|
||||
|
||||
#### 78. Consider 2 sets of points P0,P1 describing lines (2d) and a point p, how to compute distance from p to each line i (P0[i],P1[i])? (★★★)
|
||||
|
||||
|
||||
#### 78. Consider 2 sets of points P0,P1 describing lines (2d) and a point p, how to compute distance from p to each line i (P0\[i\],P1\[i\])? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 79. Consider 2 sets of points P0,P1 describing lines (2d) and a set of points P, how to compute distance from each point j (P\[j\]) to each line i (P0\[i\],P1\[i\])? (★★★)
|
||||
|
||||
|
||||
#### 79. Consider 2 sets of points P0,P1 describing lines (2d) and a set of points P, how to compute distance from each point j (P[j]) to each line i (P0[i],P1[i])? (★★★)
|
||||
|
||||
#### 80. Consider an arbitrary array, write a function that extract a subpart with a fixed shape and centered on a given element (pad with a `fill` value when necessary) (★★★)
|
||||
|
||||
#### 81. Consider an array Z = [1,2,3,4,5,6,7,8,9,10,11,12,13,14], how to generate an array R = [[1,2,3,4], [2,3,4,5], [3,4,5,6], ..., [11,12,13,14]]? (★★★)
|
||||
|
||||
|
||||
#### 81. Consider an array Z = \[1,2,3,4,5,6,7,8,9,10,11,12,13,14\], how to generate an array R = \[\[1,2,3,4\], \[2,3,4,5\], \[3,4,5,6\], ..., \[11,12,13,14\]\]? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 82. Compute a matrix rank (★★★)
|
||||
|
||||
|
||||
#### 82. Compute a matrix rank (★★★)
|
||||
|
||||
#### 83. How to find the most frequent value in an array?
|
||||
|
||||
|
||||
|
||||
#### 84. Extract all the contiguous 3x3 blocks from a random 10x10 matrix (★★★)
|
||||
|
||||
|
||||
|
||||
#### 85. Create a 2D array subclass such that Z\[i,j\] == Z\[j,i\] (★★★)
|
||||
|
||||
|
||||
#### 85. Create a 2D array subclass such that Z[i,j] == Z[j,i] (★★★)
|
||||
|
||||
#### 86. Consider a set of p matrices wich shape (n,n) and a set of p vectors with shape (n,1). How to compute the sum of of the p matrix products at once? (result has shape (n,1)) (★★★)
|
||||
|
||||
|
||||
|
||||
#### 87. Consider a 16x16 array, how to get the block-sum (block size is 4x4)? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 88. How to implement the Game of Life using numpy arrays? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 89. How to get the n largest values of an array (★★★)
|
||||
|
||||
|
||||
|
||||
#### 90. Given an arbitrary number of vectors, build the cartesian product (every combinations of every item) (★★★)
|
||||
|
||||
|
||||
|
||||
#### 91. How to create a record array from a regular array? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 92. Consider a large vector Z, compute Z to the power of 3 using 3 different methods (★★★)
|
||||
|
||||
|
||||
|
||||
#### 93. Consider two arrays A and B of shape (8,3) and (2,2). How to find rows of A that contain elements of each row of B regardless of the order of the elements in B? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 94. Considering a 10x3 matrix, extract rows with unequal values (e.g. \[2,2,3\]) (★★★)
|
||||
|
||||
|
||||
#### 94. Considering a 10x3 matrix, extract rows with unequal values (e.g. [2,2,3]) (★★★)
|
||||
|
||||
#### 95. Convert a vector of ints into a matrix binary representation (★★★)
|
||||
|
||||
|
||||
|
||||
#### 96. Given a two dimensional array, how to extract unique rows? (★★★)
|
||||
|
||||
|
||||
|
||||
#### 97. Considering 2 vectors A & B, write the einsum equivalent of inner, outer, sum, and mul function (★★★)
|
||||
|
||||
|
||||
|
||||
#### 98. Considering a path described by two vectors (X,Y), how to sample it using equidistant samples (★★★)?
|
||||
|
||||
|
||||
|
||||
#### 99. Given an integer n and a 2D array X, select from X the rows which can be interpreted as draws from a multinomial distribution with n degrees, i.e., the rows which only contain integers and which sum to n. (★★★)
|
||||
|
||||
|
||||
|
||||
#### 100. Compute bootstrapped 95% confidence intervals for the mean of a 1D array X (i.e., resample the elements of an array with replacement N times, compute the mean of each sample, and then compute percentiles over the means). (★★★)
|
||||
|
||||
55
numpy_100_random.ipynb
Normal file
55
numpy_100_random.ipynb
Normal file
@ -0,0 +1,55 @@
|
||||
{
|
||||
"cells": [
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"\n",
|
||||
"# 100 numpy exercises\n",
|
||||
"\n",
|
||||
"This is a collection of exercises that have been collected in the numpy mailing list, on stack overflow \n",
|
||||
"and in the numpy documentation. The goal of this collection is to offer a quick reference for both old \n",
|
||||
"and new users but also to provide a set of exercises for those who teach.\n",
|
||||
"\n",
|
||||
"\n",
|
||||
"If you find an error or think you've a better way to solve some of them, feel \n",
|
||||
"free to open an issue at <https://github.com/rougier/numpy-100>\n"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"File automatically generated. See the documentation to update the questions programmatically."
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"Run the `initialize.py` module, then call a random question with `pick()`an hint towards its solution with `hint(n)` and the answer with `answer(n)`,where n is the number of the picked question."
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": null,
|
||||
"metadata": {},
|
||||
"outputs": [],
|
||||
"source": [
|
||||
"%run initialise.py"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": null,
|
||||
"metadata": {},
|
||||
"outputs": [],
|
||||
"source": [
|
||||
"pick()"
|
||||
]
|
||||
}
|
||||
],
|
||||
"metadata": {},
|
||||
"nbformat": 4,
|
||||
"nbformat_minor": 2
|
||||
}
|
||||
254
numpy_100_with_hints.md
Normal file
254
numpy_100_with_hints.md
Normal file
@ -0,0 +1,254 @@
|
||||
|
||||
|
||||
|
||||
|
||||
# 100 numpy exercises
|
||||
|
||||
This is a collection of exercises that have been collected in the numpy mailing list, on stack overflow
|
||||
and in the numpy documentation. The goal of this collection is to offer a quick reference for both old
|
||||
and new users but also to provide a set of exercises for those who teach.
|
||||
|
||||
|
||||
If you find an error or think you've a better way to solve some of them, feel
|
||||
free to open an issue at <https://github.com/rougier/numpy-100>
|
||||
File automatically generated. See the documentation to update questions/answers/hints programmatically.
|
||||
#### 1. Import the numpy package under the name `np` (★☆☆)
|
||||
Hint: `hint: import … as `
|
||||
#### 2. Print the numpy version and the configuration (★☆☆)
|
||||
Hint: `hint: np.__version__, np.show_config)`
|
||||
#### 3. Create a null vector of size 10 (★☆☆)
|
||||
Hint: `hint: np.zeros`
|
||||
#### 4. How to find the memory size of any array (★☆☆)
|
||||
Hint: `hint: size, itemsize`
|
||||
#### 5. How to get the documentation of the numpy add function from the command line? (★☆☆)
|
||||
Hint: `hint: np.info`
|
||||
#### 6. Create a null vector of size 10 but the fifth value which is 1 (★☆☆)
|
||||
Hint: `hint: array[4]`
|
||||
#### 7. Create a vector with values ranging from 10 to 49 (★☆☆)
|
||||
Hint: `hint: arange`
|
||||
#### 8. Reverse a vector (first element becomes last) (★☆☆)
|
||||
Hint: `hint: array[::-1]`
|
||||
#### 9. Create a 3x3 matrix with values ranging from 0 to 8 (★☆☆)
|
||||
Hint: `hint: reshape`
|
||||
#### 10. Find indices of non-zero elements from [1,2,0,0,4,0] (★☆☆)
|
||||
Hint: `hint: np.nonzero`
|
||||
#### 11. Create a 3x3 identity matrix (★☆☆)
|
||||
Hint: `hint: np.eye`
|
||||
#### 12. Create a 3x3x3 array with random values (★☆☆)
|
||||
Hint: `hint: np.random.random`
|
||||
#### 13. Create a 10x10 array with random values and find the minimum and maximum values (★☆☆)
|
||||
Hint: `hint: min, max`
|
||||
#### 14. Create a random vector of size 30 and find the mean value (★☆☆)
|
||||
Hint: `hint: mean`
|
||||
#### 15. Create a 2d array with 1 on the border and 0 inside (★☆☆)
|
||||
Hint: `hint: array[1:-1, 1:-1]`
|
||||
#### 16. How to add a border (filled with 0's) around an existing array? (★☆☆)
|
||||
Hint: `hint: np.pad`
|
||||
#### 17. What is the result of the following expression? (★☆☆)
|
||||
```python
|
||||
0 * np.nan
|
||||
np.nan == np.nan
|
||||
np.inf > np.nan
|
||||
np.nan - np.nan
|
||||
np.nan in set([np.nan])
|
||||
0.3 == 3 * 0.1
|
||||
```
|
||||
Hint: `hint: NaN = not a number, inf = infinity`
|
||||
#### 18. Create a 5x5 matrix with values 1,2,3,4 just below the diagonal (★☆☆)
|
||||
Hint: `hint: np.diag`
|
||||
#### 19. Create a 8x8 matrix and fill it with a checkerboard pattern (★☆☆)
|
||||
Hint: `hint: array[::2]`
|
||||
#### 20. Consider a (6,7,8) shape array, what is the index (x,y,z) of the 100th element?
|
||||
Hint: `hint: np.unravel_index`
|
||||
#### 21. Create a checkerboard 8x8 matrix using the tile function (★☆☆)
|
||||
Hint: `hint: np.tile`
|
||||
#### 22. Normalize a 5x5 random matrix (★☆☆)
|
||||
Hint: `hint: (x -mean)/std`
|
||||
#### 23. Create a custom dtype that describes a color as four unsigned bytes (RGBA) (★☆☆)
|
||||
Hint: `hint: np.dtype`
|
||||
#### 24. Multiply a 5x3 matrix by a 3x2 matrix (real matrix product) (★☆☆)
|
||||
Hint: `hint: `
|
||||
#### 25. Given a 1D array, negate all elements which are between 3 and 8, in place. (★☆☆)
|
||||
Hint: `hint: >, <=`
|
||||
#### 26. What is the output of the following script? (★☆☆)
|
||||
```python
|
||||
# Author: Jake VanderPlas
|
||||
|
||||
print(sum(range(5),-1))
|
||||
from numpy import *
|
||||
print(sum(range(5),-1))
|
||||
```
|
||||
|
||||
Hint: `hint: np.sum`
|
||||
#### 27. Consider an integer vector Z, which of these expressions are legal? (★☆☆)
|
||||
```python
|
||||
Z**Z
|
||||
2 << Z >> 2
|
||||
Z <- Z
|
||||
1j*Z
|
||||
Z/1/1
|
||||
Z<Z>Z
|
||||
```
|
||||
Hint: `No hints provided...`
|
||||
#### 28. What are the result of the following expressions?
|
||||
```python
|
||||
np.array(0) / np.array(0)
|
||||
np.array(0) // np.array(0)
|
||||
np.array([np.nan]).astype(int).astype(float)
|
||||
```
|
||||
|
||||
Hint: `No hints provided... `
|
||||
#### 29. How to round away from zero a float array ? (★☆☆)
|
||||
Hint: `hint: np.uniform, np.copysign, np.ceil, np.abs`
|
||||
#### 30. How to find common values between two arrays? (★☆☆)
|
||||
Hint: `hint: np.intersect1d`
|
||||
#### 31. How to ignore all numpy warnings (not recommended)? (★☆☆)
|
||||
Hint: `hint: np.seterr, np.errstate`
|
||||
#### 32. Is the following expressions true? (★☆☆)
|
||||
```python
|
||||
np.sqrt(-1) == np.emath.sqrt(-1)
|
||||
```
|
||||
|
||||
Hint: `hint: imaginary number`
|
||||
#### 33. How to get the dates of yesterday, today and tomorrow? (★☆☆)
|
||||
Hint: `hint: np.datetime64, np.timedelta64`
|
||||
#### 34. How to get all the dates corresponding to the month of July 2016? (★★☆)
|
||||
Hint: `hint: np.arange(dtype=datetime64['D'])`
|
||||
#### 35. How to compute ((A+B)*(-A/2)) in place (without copy)? (★★☆)
|
||||
Hint: `hint: np.add(out=), np.negative(out=), np.multiply(out=), np.divide(out=)`
|
||||
#### 36. Extract the integer part of a random array using 5 different methods (★★☆)
|
||||
Hint: `hint: %, np.floor, np.ceil, astype, np.trunc`
|
||||
#### 37. Create a 5x5 matrix with row values ranging from 0 to 4 (★★☆)
|
||||
Hint: `hint: np.arange`
|
||||
#### 38. Consider a generator function that generates 10 integers and use it to build an array (★☆☆)
|
||||
Hint: `hint: np.fromiter`
|
||||
#### 39. Create a vector of size 10 with values ranging from 0 to 1, both excluded (★★☆)
|
||||
Hint: `hint: np.linspace`
|
||||
#### 40. Create a random vector of size 10 and sort it (★★☆)
|
||||
Hint: `hint: sort`
|
||||
#### 41. How to sum a small array faster than np.sum? (★★☆)
|
||||
Hint: `hint: np.add.reduce`
|
||||
#### 42. Consider two random array A and B, check if they are equal (★★☆)
|
||||
Hint: `hint: np.allclose, np.array_equal`
|
||||
#### 43. Make an array immutable (read-only) (★★☆)
|
||||
Hint: `hint: flags.writeable`
|
||||
#### 44. Consider a random 10x2 matrix representing cartesian coordinates, convert them to polar coordinates (★★☆)
|
||||
Hint: `hint: np.sqrt, np.arctan2`
|
||||
#### 45. Create random vector of size 10 and replace the maximum value by 0 (★★☆)
|
||||
Hint: `hint: argmax`
|
||||
#### 46. Create a structured array with `x` and `y` coordinates covering the [0,1]x[0,1] area (★★☆)
|
||||
Hint: `hint: np.meshgrid`
|
||||
#### 47. Given two arrays, X and Y, construct the Cauchy matrix C (Cij =1/(xi - yj))
|
||||
Hint: `hint: np.subtract.outer`
|
||||
#### 48. Print the minimum and maximum representable value for each numpy scalar type (★★☆)
|
||||
Hint: `hint: np.iinfo, np.finfo, eps`
|
||||
#### 49. How to print all the values of an array? (★★☆)
|
||||
Hint: `hint: np.set_printoptions`
|
||||
#### 50. How to find the closest value (to a given scalar) in a vector? (★★☆)
|
||||
Hint: `hint: argmin`
|
||||
#### 51. Create a structured array representing a position (x,y) and a color (r,g,b) (★★☆)
|
||||
Hint: `hint: dtype`
|
||||
#### 52. Consider a random vector with shape (100,2) representing coordinates, find point by point distances (★★☆)
|
||||
Hint: `hint: np.atleast_2d, T, np.sqrt`
|
||||
#### 53. How to convert a float (32 bits) array into an integer (32 bits) in place?
|
||||
Hint: `hint: astype(copy=False)`
|
||||
#### 54. How to read the following file? (★★☆)
|
||||
```
|
||||
1, 2, 3, 4, 5
|
||||
6, , , 7, 8
|
||||
, , 9,10,11
|
||||
```
|
||||
|
||||
Hint: `hint: np.genfromtxt`
|
||||
#### 55. What is the equivalent of enumerate for numpy arrays? (★★☆)
|
||||
Hint: `hint: np.ndenumerate, np.ndindex`
|
||||
#### 56. Generate a generic 2D Gaussian-like array (★★☆)
|
||||
Hint: `hint: np.meshgrid, np.exp`
|
||||
#### 57. How to randomly place p elements in a 2D array? (★★☆)
|
||||
Hint: `hint: np.put, np.random.choice`
|
||||
#### 58. Subtract the mean of each row of a matrix (★★☆)
|
||||
Hint: `hint: mean(axis=,keepdims=)`
|
||||
#### 59. How to sort an array by the nth column? (★★☆)
|
||||
Hint: `hint: argsort`
|
||||
#### 60. How to tell if a given 2D array has null columns? (★★☆)
|
||||
Hint: `hint: any, ~`
|
||||
#### 61. Find the nearest value from a given value in an array (★★☆)
|
||||
Hint: `hint: np.abs, argmin, flat`
|
||||
#### 62. Considering two arrays with shape (1,3) and (3,1), how to compute their sum using an iterator? (★★☆)
|
||||
Hint: `hint: np.nditer`
|
||||
#### 63. Create an array class that has a name attribute (★★☆)
|
||||
Hint: `hint: class method`
|
||||
#### 64. Consider a given vector, how to add 1 to each element indexed by a second vector (be careful with repeated indices)? (★★★)
|
||||
Hint: `hint: np.bincount | np.add.at`
|
||||
#### 65. How to accumulate elements of a vector (X) to an array (F) based on an index list (I)? (★★★)
|
||||
Hint: `hint: np.bincount`
|
||||
#### 66. Considering a (w,h,3) image of (dtype=ubyte), compute the number of unique colors (★★★)
|
||||
Hint: `hint: np.unique`
|
||||
#### 67. Considering a four dimensions array, how to get sum over the last two axis at once? (★★★)
|
||||
Hint: `hint: sum(axis=(-2,-1))`
|
||||
#### 68. Considering a one-dimensional vector D, how to compute means of subsets of D using a vector S of same size describing subset indices? (★★★)
|
||||
Hint: `hint: np.bincount`
|
||||
#### 69. How to get the diagonal of a dot product? (★★★)
|
||||
Hint: `hint: np.diag`
|
||||
#### 70. Consider the vector [1, 2, 3, 4, 5], how to build a new vector with 3 consecutive zeros interleaved between each value? (★★★)
|
||||
Hint: `hint: array[::4]`
|
||||
#### 71. Consider an array of dimension (5,5,3), how to mulitply it by an array with dimensions (5,5)? (★★★)
|
||||
Hint: `hint: array[:, :, None]`
|
||||
#### 72. How to swap two rows of an array? (★★★)
|
||||
Hint: `hint: array[[]] = array[[]]`
|
||||
#### 73. Consider a set of 10 triplets describing 10 triangles (with shared vertices), find the set of unique line segments composing all the triangles (★★★)
|
||||
Hint: `hint: repeat, np.roll, np.sort, view, np.unique`
|
||||
#### 74. Given an array C that is a bincount, how to produce an array A such that np.bincount(A) == C? (★★★)
|
||||
Hint: `hint: np.repeat`
|
||||
#### 75. How to compute averages using a sliding window over an array? (★★★)
|
||||
Hint: `hint: np.cumsum`
|
||||
#### 76. Consider a one-dimensional array Z, build a two-dimensional array whose first row is (Z[0],Z[1],Z[2]) and each subsequent row is shifted by 1 (last row should be (Z[-3],Z[-2],Z[-1]) (★★★)
|
||||
Hint: `hint: from numpy.lib import stride_tricks`
|
||||
#### 77. How to negate a boolean, or to change the sign of a float inplace? (★★★)
|
||||
Hint: `hint: np.logical_not, np.negative`
|
||||
#### 78. Consider 2 sets of points P0,P1 describing lines (2d) and a point p, how to compute distance from p to each line i (P0[i],P1[i])? (★★★)
|
||||
Hint: `No hints provided...`
|
||||
#### 79. Consider 2 sets of points P0,P1 describing lines (2d) and a set of points P, how to compute distance from each point j (P[j]) to each line i (P0[i],P1[i])? (★★★)
|
||||
Hint: `No hints provided...`
|
||||
#### 80. Consider an arbitrary array, write a function that extract a subpart with a fixed shape and centered on a given element (pad with a `fill` value when necessary) (★★★)
|
||||
Hint: `hint: minimum maximum`
|
||||
#### 81. Consider an array Z = [1,2,3,4,5,6,7,8,9,10,11,12,13,14], how to generate an array R = [[1,2,3,4], [2,3,4,5], [3,4,5,6], ..., [11,12,13,14]]? (★★★)
|
||||
Hint: `hint: stride_tricks.as_strided`
|
||||
#### 82. Compute a matrix rank (★★★)
|
||||
Hint: `hint: np.linalg.svd`
|
||||
#### 83. How to find the most frequent value in an array?
|
||||
Hint: `hint: np.bincount, argmax`
|
||||
#### 84. Extract all the contiguous 3x3 blocks from a random 10x10 matrix (★★★)
|
||||
Hint: `hint: stride_tricks.as_strided`
|
||||
#### 85. Create a 2D array subclass such that Z[i,j] == Z[j,i] (★★★)
|
||||
Hint: `hint: class method`
|
||||
#### 86. Consider a set of p matrices wich shape (n,n) and a set of p vectors with shape (n,1). How to compute the sum of of the p matrix products at once? (result has shape (n,1)) (★★★)
|
||||
Hint: `hint: np.tensordot`
|
||||
#### 87. Consider a 16x16 array, how to get the block-sum (block size is 4x4)? (★★★)
|
||||
Hint: `hint: np.add.reduceat`
|
||||
#### 88. How to implement the Game of Life using numpy arrays? (★★★)
|
||||
Hint: `No hints provided... `
|
||||
#### 89. How to get the n largest values of an array (★★★)
|
||||
Hint: `hint: np.argsort | np.argpartition`
|
||||
#### 90. Given an arbitrary number of vectors, build the cartesian product (every combinations of every item) (★★★)
|
||||
Hint: `hint: np.indices`
|
||||
#### 91. How to create a record array from a regular array? (★★★)
|
||||
Hint: `hint: np.core.records.fromarrays`
|
||||
#### 92. Consider a large vector Z, compute Z to the power of 3 using 3 different methods (★★★)
|
||||
Hint: `hint: np.power, *, np.einsum`
|
||||
#### 93. Consider two arrays A and B of shape (8,3) and (2,2). How to find rows of A that contain elements of each row of B regardless of the order of the elements in B? (★★★)
|
||||
Hint: `hint: np.where`
|
||||
#### 94. Considering a 10x3 matrix, extract rows with unequal values (e.g. [2,2,3]) (★★★)
|
||||
Hint: `No hints provided...`
|
||||
#### 95. Convert a vector of ints into a matrix binary representation (★★★)
|
||||
Hint: `hint: np.unpackbits`
|
||||
#### 96. Given a two dimensional array, how to extract unique rows? (★★★)
|
||||
Hint: `hint: np.ascontiguousarray | np.unique`
|
||||
#### 97. Considering 2 vectors A & B, write the einsum equivalent of inner, outer, sum, and mul function (★★★)
|
||||
Hint: `hint: np.einsum`
|
||||
#### 98. Considering a path described by two vectors (X,Y), how to sample it using equidistant samples (★★★)?
|
||||
Hint: `hint: np.cumsum, np.interp `
|
||||
#### 99. Given an integer n and a 2D array X, select from X the rows which can be interpreted as draws from a multinomial distribution with n degrees, i.e., the rows which only contain integers and which sum to n. (★★★)
|
||||
Hint: `hint: np.logical_and.reduce, np.mod`
|
||||
#### 100. Compute bootstrapped 95% confidence intervals for the mean of a 1D array X (i.e., resample the elements of an array with replacement N times, compute the mean of each sample, and then compute percentiles over the means). (★★★)
|
||||
Hint: `hint: np.percentile`
|
||||
1376
numpy_100_with_hints_with_solutions.md
Normal file
1376
numpy_100_with_hints_with_solutions.md
Normal file
File diff suppressed because it is too large
Load Diff
File diff suppressed because it is too large
Load Diff
@ -2,3 +2,4 @@ numpy==1.17.4
|
||||
pandas==0.25.3
|
||||
jupyter==1.0.0
|
||||
jupyterthemes==0.20.0
|
||||
mdutils==1.0.0
|
||||
|
||||
@ -1,22 +0,0 @@
|
||||
"""
|
||||
Module to automatically create the 100 exercises (with or without hints and answers)
|
||||
as a textfile format (markdown format).
|
||||
"""
|
||||
|
||||
from .questsions_dict import qha
|
||||
|
||||
|
||||
HEADER = "DO NOT MODIFY. \nFile automatically created. To modify change the content of questions_dict.py and then" \
|
||||
"re create via the python script 'create_as_textfile.py'. Search the documentation for more info."
|
||||
|
||||
|
||||
def to_markdown(destination_filename, with_ints=False, with_answers=False):
|
||||
pass
|
||||
|
||||
|
||||
def to_rst(destination_filename, with_ints=False, with_answers=False):
|
||||
pass
|
||||
|
||||
|
||||
def cli():
|
||||
pass
|
||||
Loading…
Reference in New Issue
Block a user