daviddoji/numpy-100
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Updated generated files

Browse Source
This commit is contained in:
Nicolas P. Rougier 2022-01-31 19:14:41 +01:00
parent a497e655a8
commit 2cdb74caa6
6 changed files with 317 additions and 235 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

408
100_Numpy_exercises.ipynb
View File

File diff suppressed because it is too large Load Diff

9
100_Numpy_exercises.md
View File

@ -3,12 +3,15 @@
# 100 numpy exercises
This is a collection of exercises that have been collected in the numpy mailing list, on stack overflow
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.
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.

21
100_Numpy_exercises_with_hints.md
View File

@ -3,12 +3,15 @@
# 100 numpy exercises
This is a collection of exercises that have been collected in the numpy mailing list, on stack overflow
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.
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.
@ -197,9 +200,9 @@ np.sqrt(-1) == np.emath.sqrt(-1)
#### 74. Given a sorted array C that corresponds to a bincount, how to produce an array A such that np.bincount(A) == C? (★★★)
`hint: np.repeat`
#### 75. How to compute averages using a sliding window over an array? (★★★)
`hint: np.cumsum`
`hint: np.cumsum, from numpy.lib.stride_tricks import sliding_window_view (np>=1.20.0)`
#### 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: from numpy.lib import stride_tricks`
`hint: from numpy.lib import stride_tricks, from numpy.lib.stride_tricks import sliding_window_view (np>=1.20.0)`
#### 77. How to negate a boolean, or to change the sign of a float inplace? (★★★)
`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])? (★★★)
@ -209,19 +212,19 @@ np.sqrt(-1) == np.emath.sqrt(-1)
#### 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`
#### 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`
`hint: stride_tricks.as_strided, from numpy.lib.stride_tricks import sliding_window_view (np>=1.20.0)`
#### 82. Compute a matrix rank (★★★)
`hint: np.linalg.svd`
`hint: np.linalg.svd, np.linalg.matrix_rank`
#### 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`
`hint: stride_tricks.as_strided, from numpy.lib.stride_tricks import sliding_window_view (np>=1.20.0)`
#### 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`
`hint: np.add.reduceat, from numpy.lib.stride_tricks import sliding_window_view (np>=1.20.0)`
#### 88. How to implement the Game of Life using numpy arrays? (★★★)
`No hints provided...`
#### 89. How to get the n largest values of an array (★★★)

56
100_Numpy_exercises_with_hints_with_solutions.md
View File

@ -3,12 +3,15 @@
# 100 numpy exercises
This is a collection of exercises that have been collected in the numpy mailing list, on stack overflow
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.
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.
@ -806,7 +809,7 @@ A = np.repeat(np.arange(len(C)), C)
print(A)
```
#### 75. How to compute averages using a sliding window over an array? (★★★)
`hint: np.cumsum`
`hint: np.cumsum, from numpy.lib.stride_tricks import sliding_window_view (np>=1.20.0)`
```python
# Author: Jaime Fernández del Río
@ -817,9 +820,17 @@ def moving_average(a, n=3) :
return ret[n - 1:] / n
Z = np.arange(20)
print(moving_average(Z, n=3))
# Author: Jeff Luo (@Jeff1999)
# make sure your NumPy >= 1.20.0
from numpy.lib.stride_tricks import sliding_window_view
Z = np.arange(20)
print(sliding_window_view(Z, window_shape=3).mean(axis=-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]) (★★★)
`hint: from numpy.lib import stride_tricks`
`hint: from numpy.lib import stride_tricks, from numpy.lib.stride_tricks import sliding_window_view (np>=1.20.0)`
```python
# Author: Joe Kington / Erik Rigtorp
@ -831,6 +842,11 @@ def rolling(a, window):
return stride_tricks.as_strided(a, shape=shape, strides=strides)
Z = rolling(np.arange(10), 3)
print(Z)
# Author: Jeff Luo (@Jeff1999)
Z = np.arange(10)
print(sliding_window_view(Z, window_shape=3))
```
#### 77. How to negate a boolean, or to change the sign of a float inplace? (★★★)
`hint: np.logical_not, np.negative`
@ -906,7 +922,7 @@ print(Z)
print(R)
```
#### 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`
`hint: stride_tricks.as_strided, from numpy.lib.stride_tricks import sliding_window_view (np>=1.20.0)`
```python
# Author: Stefan van der Walt
@ -914,9 +930,14 @@ print(R)
Z = np.arange(1,15,dtype=np.uint32)
R = stride_tricks.as_strided(Z,(11,4),(4,4))
print(R)
# Author: Jeff Luo (@Jeff1999)
Z = np.arange(1, 15, dtype=np.uint32)
print(sliding_window_view(Z, window_shape=4))
```
#### 82. Compute a matrix rank (★★★)
`hint: np.linalg.svd`
`hint: np.linalg.svd, np.linalg.matrix_rank`
```python
# Author: Stefan van der Walt
@ -925,6 +946,12 @@ Z = np.random.uniform(0,1,(10,10))
U, S, V = np.linalg.svd(Z) # Singular Value Decomposition
rank = np.sum(S > 1e-10)
print(rank)
# alternative solution:
# Author: Jeff Luo (@Jeff1999)
rank = np.linalg.matrix_rank(Z)
print(rank)
```
#### 83. How to find the most frequent value in an array?
`hint: np.bincount, argmax`
@ -934,7 +961,7 @@ Z = np.random.randint(0,10,50)
print(np.bincount(Z).argmax())
```
#### 84. Extract all the contiguous 3x3 blocks from a random 10x10 matrix (★★★)
`hint: stride_tricks.as_strided`
`hint: stride_tricks.as_strided, from numpy.lib.stride_tricks import sliding_window_view (np>=1.20.0)`
```python
# Author: Chris Barker
@ -945,6 +972,11 @@ i = 1 + (Z.shape[0]-3)
j = 1 + (Z.shape[1]-3)
C = stride_tricks.as_strided(Z, shape=(i, j, n, n), strides=Z.strides + Z.strides)
print(C)
# Author: Jeff Luo (@Jeff1999)
Z = np.random.randint(0,5,(10,10))
print(sliding_window_view(Z, window_shape=(3, 3)))
```
#### 85. Create a 2D array subclass such that Z[i,j] == Z[j,i] (★★★)
`hint: class method`
@ -985,7 +1017,7 @@ print(S)
# and 2 and 1, to remain with a (n,1) vector.
```
#### 87. Consider a 16x16 array, how to get the block-sum (block size is 4x4)? (★★★)
`hint: np.add.reduceat`
`hint: np.add.reduceat, from numpy.lib.stride_tricks import sliding_window_view (np>=1.20.0)`
```python
# Author: Robert Kern
@ -1004,6 +1036,12 @@ k = 4
windows = np.lib.stride_tricks.sliding_window_view(Z, (k, k))
S = windows[::k, ::k, ...].sum(axis=(-2, -1))
# Author: Jeff Luo (@Jeff1999)
Z = np.ones((16, 16))
k = 4
print(sliding_window_view(Z, window_shape=(k, k))[::k, ::k].sum(axis=(-2, -1)))
```
#### 88. How to implement the Game of Life using numpy arrays? (★★★)
`No hints provided...`

48
100_Numpy_exercises_with_solutions.md
View File

@ -3,12 +3,15 @@
# 100 numpy exercises
This is a collection of exercises that have been collected in the numpy mailing list, on stack overflow
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.
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.
@ -178,7 +181,7 @@ print(np.unravel_index(99,(6,7,8)))
```python
Z = np.tile(np.eye(2), (4,4))
Z = np.tile( np.array([[0,1],[1,0]]), (4,4))
print(Z)
```
#### 22. Normalize a 5x5 random matrix (★☆☆)
@ -817,6 +820,14 @@ def moving_average(a, n=3) :
return ret[n - 1:] / n
Z = np.arange(20)
print(moving_average(Z, n=3))
# Author: Jeff Luo (@Jeff1999)
# make sure your NumPy >= 1.20.0
from numpy.lib.stride_tricks import sliding_window_view
Z = np.arange(20)
print(sliding_window_view(Z, window_shape=3).mean(axis=-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]) (★★★)
@ -831,6 +842,11 @@ def rolling(a, window):
return stride_tricks.as_strided(a, shape=shape, strides=strides)
Z = rolling(np.arange(10), 3)
print(Z)
# Author: Jeff Luo (@Jeff1999)
Z = np.arange(10)
print(sliding_window_view(Z, window_shape=3))
```
#### 77. How to negate a boolean, or to change the sign of a float inplace? (★★★)
@ -914,6 +930,11 @@ print(R)
Z = np.arange(1,15,dtype=np.uint32)
R = stride_tricks.as_strided(Z,(11,4),(4,4))
print(R)
# Author: Jeff Luo (@Jeff1999)
Z = np.arange(1, 15, dtype=np.uint32)
print(sliding_window_view(Z, window_shape=4))
```
#### 82. Compute a matrix rank (★★★)
@ -925,6 +946,12 @@ Z = np.random.uniform(0,1,(10,10))
U, S, V = np.linalg.svd(Z) # Singular Value Decomposition
rank = np.sum(S > 1e-10)
print(rank)
# alternative solution:
# Author: Jeff Luo (@Jeff1999)
rank = np.linalg.matrix_rank(Z)
print(rank)
```
#### 83. How to find the most frequent value in an array?
@ -945,6 +972,11 @@ i = 1 + (Z.shape[0]-3)
j = 1 + (Z.shape[1]-3)
C = stride_tricks.as_strided(Z, shape=(i, j, n, n), strides=Z.strides + Z.strides)
print(C)
# Author: Jeff Luo (@Jeff1999)
Z = np.random.randint(0,5,(10,10))
print(sliding_window_view(Z, window_shape=(3, 3)))
```
#### 85. Create a 2D array subclass such that Z[i,j] == Z[j,i] (★★★)
@ -1004,6 +1036,12 @@ k = 4
windows = np.lib.stride_tricks.sliding_window_view(Z, (k, k))
S = windows[::k, ::k, ...].sum(axis=(-2, -1))
# Author: Jeff Luo (@Jeff1999)
Z = np.ones((16, 16))
k = 4
print(sliding_window_view(Z, window_shape=(k, k))[::k, ::k].sum(axis=(-2, -1)))
```
#### 88. How to implement the Game of Life using numpy arrays? (★★★)
@ -1205,4 +1243,4 @@ idx = np.random.randint(0, X.size, (N, X.size))
means = X[idx].mean(axis=1)
confint = np.percentile(means, [2.5, 97.5])
print(confint)
```
```

10
100_Numpy_random.ipynb
View File

@ -2,7 +2,7 @@
"cells": [
{
"cell_type": "markdown",
"id": "bbe15f43",
"id": "a194d42e",
"metadata": {},
"source": [
"# 100 numpy exercises\n",
@ -18,7 +18,7 @@
},
{
"cell_type": "markdown",
"id": "ed56e5f0",
"id": "a7fd49f7",
"metadata": {},
"source": [
"File automatically generated. See the documentation to update questions/answers/hints programmatically."
@ -26,7 +26,7 @@
},
{
"cell_type": "markdown",
"id": "14866554",
"id": "b702d5a2",
"metadata": {},
"source": [
"Run the `initialize.py` module, then call a random question with `pick()` an hint towards its solution with\n",
@ -36,7 +36,7 @@
{
"cell_type": "code",
"execution_count": null,
"id": "af8b6f2a",
"id": "da60e1d0",
"metadata": {},
"outputs": [],
"source": [
@ -46,7 +46,7 @@
{
"cell_type": "code",
"execution_count": null,
"id": "f13ecfd7",
"id": "9fb544fe",
"metadata": {},
"outputs": [],
"source": [