add difficulty

100_Numpy_exercises.md

@@ -58,7 +58,7 @@ np.nan in set([np.nan])
 
 #### 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?
+#### 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 (★☆☆)
 
@@ -89,7 +89,7 @@ Z/1/1
 Z<Z>Z
 ```
 
-#### 28. What are the result of the following expressions?
+#### 28. What are the result of the following expressions? (★☆☆)
 ```python
 np.array(0) / np.array(0)
 np.array(0) // np.array(0)
@@ -135,7 +135,7 @@ np.sqrt(-1) == np.emath.sqrt(-1)
 
 #### 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 (★★☆)
 

100_Numpy_exercises_with_hints.md

@@ -58,7 +58,7 @@ np.nan in set([np.nan])
 `hint: np.diag`
 #### 19. Create a 8x8 matrix and fill it with a checkerboard pattern (★☆☆)
 `hint: array[::2]`
-#### 20. Consider a (6,7,8) shape array, what is the index (x,y,z) of the 100th element?
+#### 20. Consider a (6,7,8) shape array, what is the index (x,y,z) of the 100th element? (★☆☆)
 `hint: np.unravel_index`
 #### 21. Create a checkerboard 8x8 matrix using the tile function (★☆☆)
 `hint: np.tile`
@@ -89,7 +89,7 @@ Z/1/1
 Z<Z>Z
 ```
 `No hints provided...`
-#### 28. What are the result of the following expressions?
+#### 28. What are the result of the following expressions? (★☆☆)
 ```python
 np.array(0) / np.array(0)
 np.array(0) // np.array(0)
@@ -135,7 +135,7 @@ np.sqrt(-1) == np.emath.sqrt(-1)
 `hint: argmax`
 #### 46. Create a structured array with `x` and `y` coordinates covering the [0,1]x[0,1] area (★★☆)
 `hint: np.meshgrid`
-#### 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)) (★★☆)
 `hint: np.subtract.outer`
 #### 48. Print the minimum and maximum representable value for each numpy scalar type (★★☆)
 `hint: np.iinfo, np.finfo, eps`

100_Numpy_exercises_with_hints_with_solutions.md

@@ -168,7 +168,7 @@ Z[1::2,::2] = 1
 Z[::2,1::2] = 1
 print(Z)
 ```
-#### 20. Consider a (6,7,8) shape array, what is the index (x,y,z) of the 100th element?
+#### 20. Consider a (6,7,8) shape array, what is the index (x,y,z) of the 100th element? (★☆☆)
 `hint: np.unravel_index`
 
 ```python
@@ -255,7 +255,7 @@ Z <- Z
 Z/1/1
 Z<Z>Z
 ```
-#### 28. What are the result of the following expressions?
+#### 28. What are the result of the following expressions? (★☆☆)
 ```python
 np.array(0) / np.array(0)
 np.array(0) // np.array(0)
@@ -447,7 +447,7 @@ Z['x'], Z['y'] = np.meshgrid(np.linspace(0,1,5),
                              np.linspace(0,1,5))
 print(Z)
 ```
-#### 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)) (★★☆)
 `hint: np.subtract.outer`
 
 ```python
@@ -827,7 +827,7 @@ from numpy.lib import stride_tricks
 
 def rolling(a, window):
     shape = (a.size - window + 1, window)
-    strides = (a.itemsize, a.itemsize)
+    strides = (a.strides[0], a.strides[0])
     return stride_tricks.as_strided(a, shape=shape, strides=strides)
 Z = rolling(np.arange(10), 3)
 print(Z)

100_Numpy_exercises_with_solutions.md

@@ -168,7 +168,7 @@ Z[1::2,::2] = 1
 Z[::2,1::2] = 1
 print(Z)
 ```
-#### 20. Consider a (6,7,8) shape array, what is the index (x,y,z) of the 100th element?
+#### 20. Consider a (6,7,8) shape array, what is the index (x,y,z) of the 100th element? (★☆☆)
 
 
 ```python
@@ -255,7 +255,7 @@ Z <- Z
 Z/1/1
 Z<Z>Z
 ```
-#### 28. What are the result of the following expressions?
+#### 28. What are the result of the following expressions? (★☆☆)
 ```python
 np.array(0) / np.array(0)
 np.array(0) // np.array(0)
@@ -447,7 +447,7 @@ Z['x'], Z['y'] = np.meshgrid(np.linspace(0,1,5),
                              np.linspace(0,1,5))
 print(Z)
 ```
-#### 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)) (★★☆)
 
 
 ```python
@@ -827,7 +827,7 @@ from numpy.lib import stride_tricks
 
 def rolling(a, window):
     shape = (a.size - window + 1, window)
-    strides = (a.itemsize, a.itemsize)
+    strides = (a.strides[0], a.strides[0])
     return stride_tricks.as_strided(a, shape=shape, strides=strides)
 Z = rolling(np.arange(10), 3)
 print(Z)

100_Numpy_random.ipynb

@@ -2,7 +2,7 @@
  "cells": [
   {
    "cell_type": "markdown",
-   "id": "9187d1fe",
+   "id": "bbe15f43",
    "metadata": {},
    "source": [
     "# 100 numpy exercises\n",
@@ -18,7 +18,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "7b3fced0",
+   "id": "ed56e5f0",
    "metadata": {},
    "source": [
     "File automatically generated. See the documentation to update questions/answers/hints programmatically."
@@ -26,7 +26,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "77575766",
+   "id": "14866554",
    "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": "bcf0dd93",
+   "id": "af8b6f2a",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -46,7 +46,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "f401c090",
+   "id": "f13ecfd7",
    "metadata": {},
    "outputs": [],
    "source": [

source/exercises100.ktx

@@ -212,7 +212,7 @@ Z[::2,1::2] = 1
 print(Z)
 
 < q20
-Consider a (6,7,8) shape array, what is the index (x,y,z) of the 100th element?
+Consider a (6,7,8) shape array, what is the index (x,y,z) of the 100th element? (★☆☆)
 
 < h20
 hint: np.unravel_index
@@ -323,7 +323,7 @@ Z/1/1
 Z<Z>Z
 
 < q28
-What are the result of the following expressions?
+What are the result of the following expressions? (★☆☆)
 ```python
 np.array(0) / np.array(0)
 np.array(0) // np.array(0)
@@ -572,7 +572,7 @@ Z['x'], Z['y'] = np.meshgrid(np.linspace(0,1,5),
 print(Z)
 
 < q47
-Given two arrays, X and Y, construct the Cauchy matrix C (Cij =1/(xi - yj))
+Given two arrays, X and Y, construct the Cauchy matrix C (Cij =1/(xi - yj)) (★★☆)
 
 < h47
 hint: np.subtract.outer