numpy_exercises.ipynb

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  "nbformat_minor": 5,
  "metadata": {
    "colab": {
      "name": "numpy_exercises.ipynb",
      "provenance": []
    }
  },
  "cells": [
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "bf79c78b"
      },
      "source": [
        "# 100 numpy exercises\n",
        "\n"
      ],
      "id": "bf79c78b"
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "017db353"
      },
      "source": [
        "#### 1. Import the numpy package under the name `np` (★☆☆)"
      ],
      "id": "017db353"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "68182a76"
      },
      "source": [
        ""
      ],
      "id": "68182a76",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "46950f4f"
      },
      "source": [
        "#### 2. Print the numpy version and the configuration (★☆☆)"
      ],
      "id": "46950f4f"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "2a9f5838"
      },
      "source": [
        ""
      ],
      "id": "2a9f5838",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "e3c20b3d"
      },
      "source": [
        "#### 3. Create a null vector of size 10 (★☆☆)"
      ],
      "id": "e3c20b3d"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "8a758bcf"
      },
      "source": [
        ""
      ],
      "id": "8a758bcf",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "b15a879f"
      },
      "source": [
        "#### 4. How to find the memory size of any array (★☆☆)"
      ],
      "id": "b15a879f"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "1cc3cbc5"
      },
      "source": [
        ""
      ],
      "id": "1cc3cbc5",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "0a708990"
      },
      "source": [
        "#### 5. How to get the documentation of the numpy add function from the command line? (★☆☆)"
      ],
      "id": "0a708990"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "477e01f4"
      },
      "source": [
        ""
      ],
      "id": "477e01f4",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "0b16cd77"
      },
      "source": [
        "#### 6. Create a null vector of size 10 but the fifth value which is 1 (★☆☆)"
      ],
      "id": "0b16cd77"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "4d9b5975"
      },
      "source": [
        ""
      ],
      "id": "4d9b5975",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "782d4c77"
      },
      "source": [
        "#### 7. Create a vector with values ranging from 10 to 49 (★☆☆)"
      ],
      "id": "782d4c77"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "5dbe1a08"
      },
      "source": [
        ""
      ],
      "id": "5dbe1a08",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "48d48f01"
      },
      "source": [
        "#### 8. Reverse a vector (first element becomes last) (★☆☆)"
      ],
      "id": "48d48f01"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "3ed233e7"
      },
      "source": [
        ""
      ],
      "id": "3ed233e7",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "4fa39382"
      },
      "source": [
        "#### 9. Create a 3x3 matrix with values ranging from 0 to 8 (★☆☆)"
      ],
      "id": "4fa39382"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "c97757ec"
      },
      "source": [
        ""
      ],
      "id": "c97757ec",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "da64551a"
      },
      "source": [
        "#### 10. Find indices of non-zero elements from [1,2,0,0,4,0] (★☆☆)"
      ],
      "id": "da64551a"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "327f7adb"
      },
      "source": [
        ""
      ],
      "id": "327f7adb",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "f89d9c9e"
      },
      "source": [
        "#### 11. Create a 3x3 identity matrix (★☆☆)"
      ],
      "id": "f89d9c9e"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "ba625832"
      },
      "source": [
        ""
      ],
      "id": "ba625832",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "7e44c6fa"
      },
      "source": [
        "#### 12. Create a 3x3x3 array with random values (★☆☆)"
      ],
      "id": "7e44c6fa"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "1cb3dddf"
      },
      "source": [
        ""
      ],
      "id": "1cb3dddf",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "13c5928c"
      },
      "source": [
        "#### 13. Create a 10x10 array with random values and find the minimum and maximum values (★☆☆)"
      ],
      "id": "13c5928c"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "911c9b93"
      },
      "source": [
        ""
      ],
      "id": "911c9b93",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "3fa2e461"
      },
      "source": [
        "#### 14. Create a random vector of size 30 and find the mean value (★☆☆)"
      ],
      "id": "3fa2e461"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "323eb38a"
      },
      "source": [
        ""
      ],
      "id": "323eb38a",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "73f7a549"
      },
      "source": [
        "#### 15. Create a 2d array with 1 on the border and 0 inside (★☆☆)"
      ],
      "id": "73f7a549"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "e3a6807d"
      },
      "source": [
        ""
      ],
      "id": "e3a6807d",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "6d0c506f"
      },
      "source": [
        "#### 16. How to add a border (filled with 0's) around an existing array? (★☆☆)"
      ],
      "id": "6d0c506f"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "32ffee7b"
      },
      "source": [
        ""
      ],
      "id": "32ffee7b",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "d6ad1a9f"
      },
      "source": [
        "#### 17. What is the result of the following expression? (★☆☆)\n",
        "```python\n",
        "0 * np.nan\n",
        "np.nan == np.nan\n",
        "np.inf > np.nan\n",
        "np.nan - np.nan\n",
        "np.nan in set([np.nan])\n",
        "0.3 == 3 * 0.1\n",
        "```"
      ],
      "id": "d6ad1a9f"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "ee7ff0f3"
      },
      "source": [
        ""
      ],
      "id": "ee7ff0f3",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "e3a7ba7f"
      },
      "source": [
        "#### 18. Create a 5x5 matrix with values 1,2,3,4 just below the diagonal (★☆☆)"
      ],
      "id": "e3a7ba7f"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "01d8e257"
      },
      "source": [
        ""
      ],
      "id": "01d8e257",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "6d17ab5d"
      },
      "source": [
        "#### 19. Create a 8x8 matrix and fill it with a checkerboard pattern (★☆☆)"
      ],
      "id": "6d17ab5d"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "841373cd"
      },
      "source": [
        ""
      ],
      "id": "841373cd",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "8837119b"
      },
      "source": [
        "#### 20. Consider a (6,7,8) shape array, what is the index (x,y,z) of the 100th element? (★☆☆)"
      ],
      "id": "8837119b"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "2c0d16f1"
      },
      "source": [
        ""
      ],
      "id": "2c0d16f1",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "ec788c9f"
      },
      "source": [
        "#### 21. Create a checkerboard 8x8 matrix using the tile function (★☆☆)"
      ],
      "id": "ec788c9f"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "0a4f919f"
      },
      "source": [
        ""
      ],
      "id": "0a4f919f",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "391791e0"
      },
      "source": [
        "#### 22. Normalize a 5x5 random matrix (★☆☆)"
      ],
      "id": "391791e0"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "f6533d39"
      },
      "source": [
        ""
      ],
      "id": "f6533d39",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "1e74d39e"
      },
      "source": [
        "#### 23. Create a custom dtype that describes a color as four unsigned bytes (RGBA) (★☆☆)"
      ],
      "id": "1e74d39e"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "3f639d33"
      },
      "source": [
        ""
      ],
      "id": "3f639d33",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "78250c14"
      },
      "source": [
        "#### 24. Multiply a 5x3 matrix by a 3x2 matrix (real matrix product) (★☆☆)"
      ],
      "id": "78250c14"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "9fe729cb"
      },
      "source": [
        ""
      ],
      "id": "9fe729cb",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "51898680"
      },
      "source": [
        "#### 25. Given a 1D array, negate all elements which are between 3 and 8, in place. (★☆☆)"
      ],
      "id": "51898680"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "51c90f2d"
      },
      "source": [
        ""
      ],
      "id": "51c90f2d",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "89e78048"
      },
      "source": [
        "#### 26. What is the output of the following script? (★☆☆)\n",
        "```python\n",
        "# Author: Jake VanderPlas\n",
        "\n",
        "print(sum(range(5),-1))\n",
        "from numpy import *\n",
        "print(sum(range(5),-1))\n",
        "```"
      ],
      "id": "89e78048"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "b62e9d1c"
      },
      "source": [
        ""
      ],
      "id": "b62e9d1c",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "ebd10810"
      },
      "source": [
        "#### 27. Consider an integer vector Z, which of these expressions are legal? (★☆☆)\n",
        "```python\n",
        "Z**Z\n",
        "2 << Z >> 2\n",
        "Z <- Z\n",
        "1j*Z\n",
        "Z/1/1\n",
        "Z<Z>Z\n",
        "```"
      ],
      "id": "ebd10810"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "6ada209f"
      },
      "source": [
        ""
      ],
      "id": "6ada209f",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "c0e940f8"
      },
      "source": [
        "#### 28. What are the result of the following expressions? (★☆☆)\n",
        "```python\n",
        "np.array(0) / np.array(0)\n",
        "np.array(0) // np.array(0)\n",
        "np.array([np.nan]).astype(int).astype(float)\n",
        "```"
      ],
      "id": "c0e940f8"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "820dc7a5"
      },
      "source": [
        ""
      ],
      "id": "820dc7a5",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "22713c3f"
      },
      "source": [
        "#### 29. How to round away from zero a float array ? (★☆☆)"
      ],
      "id": "22713c3f"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "a3e05c29"
      },
      "source": [
        ""
      ],
      "id": "a3e05c29",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "f1ae2c2d"
      },
      "source": [
        "#### 30. How to find common values between two arrays? (★☆☆)"
      ],
      "id": "f1ae2c2d"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "6801c73d"
      },
      "source": [
        ""
      ],
      "id": "6801c73d",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "34a7bdee"
      },
      "source": [
        "#### 31. How to ignore all numpy warnings (not recommended)? (★☆☆)"
      ],
      "id": "34a7bdee"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "befc60d1"
      },
      "source": [
        ""
      ],
      "id": "befc60d1",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "37bc0973"
      },
      "source": [
        "#### 32. Is the following expressions true? (★☆☆)\n",
        "```python\n",
        "np.sqrt(-1) == np.emath.sqrt(-1)\n",
        "```"
      ],
      "id": "37bc0973"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "c70cbabe"
      },
      "source": [
        ""
      ],
      "id": "c70cbabe",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "129c342d"
      },
      "source": [
        "#### 33. How to get the dates of yesterday, today and tomorrow? (★☆☆)"
      ],
      "id": "129c342d"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "8ba1badb"
      },
      "source": [
        ""
      ],
      "id": "8ba1badb",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "42f8b2f9"
      },
      "source": [
        "#### 34. How to get all the dates corresponding to the month of July 2016? (★★☆)"
      ],
      "id": "42f8b2f9"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "eb8ebe45"
      },
      "source": [
        ""
      ],
      "id": "eb8ebe45",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "252c43e2"
      },
      "source": [
        "#### 35. How to compute ((A+B)*(-A/2)) in place (without copy)? (★★☆)"
      ],
      "id": "252c43e2"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "f06ff615"
      },
      "source": [
        ""
      ],
      "id": "f06ff615",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "486df8ea"
      },
      "source": [
        "#### 36. Extract the integer part of a random array of positive numbers using 4 different methods (★★☆)"
      ],
      "id": "486df8ea"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "34b4fa08"
      },
      "source": [
        ""
      ],
      "id": "34b4fa08",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "649e89f9"
      },
      "source": [
        "#### 37. Create a 5x5 matrix with row values ranging from 0 to 4 (★★☆)"
      ],
      "id": "649e89f9"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "663cc611"
      },
      "source": [
        ""
      ],
      "id": "663cc611",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "3421e17f"
      },
      "source": [
        "#### 38. Consider a generator function that generates 10 integers and use it to build an array (★☆☆)"
      ],
      "id": "3421e17f"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "7336b8e4"
      },
      "source": [
        ""
      ],
      "id": "7336b8e4",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "483dd554"
      },
      "source": [
        "#### 39. Create a vector of size 10 with values ranging from 0 to 1, both excluded (★★☆)"
      ],
      "id": "483dd554"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "c89b93e7"
      },
      "source": [
        ""
      ],
      "id": "c89b93e7",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "2d07be1c"
      },
      "source": [
        "#### 40. Create a random vector of size 10 and sort it (★★☆)"
      ],
      "id": "2d07be1c"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "4f7cb3ad"
      },
      "source": [
        ""
      ],
      "id": "4f7cb3ad",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "6415f02e"
      },
      "source": [
        "#### 41. How to sum a small array faster than np.sum? (★★☆)"
      ],
      "id": "6415f02e"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "bb0dd942"
      },
      "source": [
        ""
      ],
      "id": "bb0dd942",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "fe043549"
      },
      "source": [
        "#### 42. Consider two random array A and B, check if they are equal (★★☆)"
      ],
      "id": "fe043549"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "3326a686"
      },
      "source": [
        ""
      ],
      "id": "3326a686",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "cc08f71c"
      },
      "source": [
        "#### 43. Make an array immutable (read-only) (★★☆)"
      ],
      "id": "cc08f71c"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "d5cc9dbe"
      },
      "source": [
        ""
      ],
      "id": "d5cc9dbe",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "2002cb03"
      },
      "source": [
        "#### 44. Consider a random 10x2 matrix representing cartesian coordinates, convert them to polar coordinates (★★☆)"
      ],
      "id": "2002cb03"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "58be72bc"
      },
      "source": [
        ""
      ],
      "id": "58be72bc",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "b7109c9f"
      },
      "source": [
        "#### 45. Create random vector of size 10 and replace the maximum value by 0 (★★☆)"
      ],
      "id": "b7109c9f"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "f79e79a7"
      },
      "source": [
        ""
      ],
      "id": "f79e79a7",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "7d3131b9"
      },
      "source": [
        "#### 46. Create a structured array with `x` and `y` coordinates covering the [0,1]x[0,1] area (★★☆)"
      ],
      "id": "7d3131b9"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "4f471afe"
      },
      "source": [
        ""
      ],
      "id": "4f471afe",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "7c8c1fc5"
      },
      "source": [
        "#### 47. Given two arrays, X and Y, construct the Cauchy matrix C (Cij =1/(xi - yj)) (★★☆)"
      ],
      "id": "7c8c1fc5"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "8fac7d28"
      },
      "source": [
        ""
      ],
      "id": "8fac7d28",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "5795b4bd"
      },
      "source": [
        "#### 48. Print the minimum and maximum representable value for each numpy scalar type (★★☆)"
      ],
      "id": "5795b4bd"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "b721f7ca"
      },
      "source": [
        ""
      ],
      "id": "b721f7ca",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "fb24674c"
      },
      "source": [
        "#### 49. How to print all the values of an array? (★★☆)"
      ],
      "id": "fb24674c"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "c81f1456"
      },
      "source": [
        ""
      ],
      "id": "c81f1456",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "e6e1ae2f"
      },
      "source": [
        "#### 50. How to find the closest value (to a given scalar) in a vector? (★★☆)"
      ],
      "id": "e6e1ae2f"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "73dd91cc"
      },
      "source": [
        ""
      ],
      "id": "73dd91cc",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "c01f0ecf"
      },
      "source": [
        "#### 51. Create a structured array representing a position (x,y) and a color (r,g,b) (★★☆)"
      ],
      "id": "c01f0ecf"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "fb8017ca"
      },
      "source": [
        ""
      ],
      "id": "fb8017ca",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "3b64a18b"
      },
      "source": [
        "#### 52. Consider a random vector with shape (100,2) representing coordinates, find point by point distances (★★☆)"
      ],
      "id": "3b64a18b"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "4b482822"
      },
      "source": [
        ""
      ],
      "id": "4b482822",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "48413134"
      },
      "source": [
        "#### 53. How to convert a float (32 bits) array into an integer (32 bits) in place?"
      ],
      "id": "48413134"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "5db64b6d"
      },
      "source": [
        ""
      ],
      "id": "5db64b6d",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "0a532633"
      },
      "source": [
        "#### 54. How to read the following file? (★★☆)\n",
        "```\n",
        "1, 2, 3, 4, 5\n",
        "6,  ,  , 7, 8\n",
        " ,  , 9,10,11\n",
        "```"
      ],
      "id": "0a532633"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "8af4f753"
      },
      "source": [
        ""
      ],
      "id": "8af4f753",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "f98713a6"
      },
      "source": [
        "#### 55. What is the equivalent of enumerate for numpy arrays? (★★☆)"
      ],
      "id": "f98713a6"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "64795f84"
      },
      "source": [
        ""
      ],
      "id": "64795f84",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "1abc7cc8"
      },
      "source": [
        "#### 56. Generate a generic 2D Gaussian-like array (★★☆)"
      ],
      "id": "1abc7cc8"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "42e3a5bc"
      },
      "source": [
        ""
      ],
      "id": "42e3a5bc",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "0cf413ee"
      },
      "source": [
        "#### 57. How to randomly place p elements in a 2D array? (★★☆)"
      ],
      "id": "0cf413ee"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "dfc57e06"
      },
      "source": [
        ""
      ],
      "id": "dfc57e06",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "215b6acc"
      },
      "source": [
        "#### 58. Subtract the mean of each row of a matrix (★★☆)"
      ],
      "id": "215b6acc"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "dd1adef4"
      },
      "source": [
        ""
      ],
      "id": "dd1adef4",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "c0cf37e0"
      },
      "source": [
        "#### 59. How to sort an array by the nth column? (★★☆)"
      ],
      "id": "c0cf37e0"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "9336ca5f"
      },
      "source": [
        ""
      ],
      "id": "9336ca5f",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "c17fb213"
      },
      "source": [
        "#### 60. How to tell if a given 2D array has null columns? (★★☆)"
      ],
      "id": "c17fb213"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "7fdda78d"
      },
      "source": [
        ""
      ],
      "id": "7fdda78d",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "8aaab886"
      },
      "source": [
        "#### 61. Find the nearest value from a given value in an array (★★☆)"
      ],
      "id": "8aaab886"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "973f8079"
      },
      "source": [
        ""
      ],
      "id": "973f8079",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "66a04e2e"
      },
      "source": [
        "#### 62. Considering two arrays with shape (1,3) and (3,1), how to compute their sum using an iterator? (★★☆)"
      ],
      "id": "66a04e2e"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "4b356632"
      },
      "source": [
        ""
      ],
      "id": "4b356632",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "f4427f7f"
      },
      "source": [
        "#### 63. Create an array class that has a name attribute (★★☆)"
      ],
      "id": "f4427f7f"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "fe253212"
      },
      "source": [
        ""
      ],
      "id": "fe253212",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "58be9dd4"
      },
      "source": [
        "#### 64. Consider a given vector, how to add 1 to each element indexed by a second vector (be careful with repeated indices)? (★★★)"
      ],
      "id": "58be9dd4"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "5c8bae42"
      },
      "source": [
        ""
      ],
      "id": "5c8bae42",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "7348abd0"
      },
      "source": [
        "#### 65. How to accumulate elements of a vector (X) to an array (F) based on an index list (I)? (★★★)"
      ],
      "id": "7348abd0"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "b3e33a5a"
      },
      "source": [
        ""
      ],
      "id": "b3e33a5a",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "538e651c"
      },
      "source": [
        "#### 66. Considering a (w,h,3) image of (dtype=ubyte), compute the number of unique colors (★★☆)"
      ],
      "id": "538e651c"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "57f2f02f"
      },
      "source": [
        ""
      ],
      "id": "57f2f02f",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "33c986d9"
      },
      "source": [
        "#### 67. Considering a four dimensions array, how to get sum over the last two axis at once? (★★★)"
      ],
      "id": "33c986d9"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "a99a50e2"
      },
      "source": [
        ""
      ],
      "id": "a99a50e2",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "00eb27c4"
      },
      "source": [
        "#### 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? (★★★)"
      ],
      "id": "00eb27c4"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "d48c5210"
      },
      "source": [
        ""
      ],
      "id": "d48c5210",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "928a1a15"
      },
      "source": [
        "#### 69. How to get the diagonal of a dot product? (★★★)"
      ],
      "id": "928a1a15"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "ef2c9ddd"
      },
      "source": [
        ""
      ],
      "id": "ef2c9ddd",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "5143f7f3"
      },
      "source": [
        "#### 70. Consider the vector [1, 2, 3, 4, 5], how to build a new vector with 3 consecutive zeros interleaved between each value? (★★★)"
      ],
      "id": "5143f7f3"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "1d99a1c1"
      },
      "source": [
        ""
      ],
      "id": "1d99a1c1",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "f62551d8"
      },
      "source": [
        "#### 71. Consider an array of dimension (5,5,3), how to mulitply it by an array with dimensions (5,5)? (★★★)"
      ],
      "id": "f62551d8"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "9ab241b7"
      },
      "source": [
        ""
      ],
      "id": "9ab241b7",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "6896e326"
      },
      "source": [
        "#### 72. How to swap two rows of an array? (★★★)"
      ],
      "id": "6896e326"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "9e8fcba9"
      },
      "source": [
        ""
      ],
      "id": "9e8fcba9",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "aeaf4a7b"
      },
      "source": [
        "#### 73. Consider a set of 10 triplets describing 10 triangles (with shared vertices), find the set of unique line segments composing all the  triangles (★★★)"
      ],
      "id": "aeaf4a7b"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "39ef4234"
      },
      "source": [
        ""
      ],
      "id": "39ef4234",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "3d11451b"
      },
      "source": [
        "#### 74. Given a sorted array C that corresponds to a bincount, how to produce an array A such that np.bincount(A) == C? (★★★)"
      ],
      "id": "3d11451b"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "a5563362"
      },
      "source": [
        ""
      ],
      "id": "a5563362",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "a0a45995"
      },
      "source": [
        "#### 75. How to compute averages using a sliding window over an array? (★★★)"
      ],
      "id": "a0a45995"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "116243d5"
      },
      "source": [
        ""
      ],
      "id": "116243d5",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "7808578f"
      },
      "source": [
        "#### 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]) (★★★)"
      ],
      "id": "7808578f"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "6b23ba6e"
      },
      "source": [
        ""
      ],
      "id": "6b23ba6e",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "8e83df46"
      },
      "source": [
        "#### 77. How to negate a boolean, or to change the sign of a float inplace? (★★★)"
      ],
      "id": "8e83df46"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "f73127b7"
      },
      "source": [
        ""
      ],
      "id": "f73127b7",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "e67ff31c"
      },
      "source": [
        "#### 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])? (★★★)"
      ],
      "id": "e67ff31c"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "89d75b76"
      },
      "source": [
        ""
      ],
      "id": "89d75b76",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "ad8821b1"
      },
      "source": [
        "#### 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])? (★★★)"
      ],
      "id": "ad8821b1"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "775feca0"
      },
      "source": [
        ""
      ],
      "id": "775feca0",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "a0c8cbf5"
      },
      "source": [
        "#### 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) (★★★)"
      ],
      "id": "a0c8cbf5"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "381fd926"
      },
      "source": [
        ""
      ],
      "id": "381fd926",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "781fa236"
      },
      "source": [
        "#### 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]]? (★★★)"
      ],
      "id": "781fa236"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "8e84d3c2"
      },
      "source": [
        ""
      ],
      "id": "8e84d3c2",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "9c9bb0f3"
      },
      "source": [
        "#### 82. Compute a matrix rank (★★★)"
      ],
      "id": "9c9bb0f3"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "b75ef318"
      },
      "source": [
        ""
      ],
      "id": "b75ef318",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "7d8dc135"
      },
      "source": [
        "#### 83. How to find the most frequent value in an array?"
      ],
      "id": "7d8dc135"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "3978a7a2"
      },
      "source": [
        ""
      ],
      "id": "3978a7a2",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "aa340126"
      },
      "source": [
        "#### 84. Extract all the contiguous 3x3 blocks from a random 10x10 matrix (★★★)"
      ],
      "id": "aa340126"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "bf138783"
      },
      "source": [
        ""
      ],
      "id": "bf138783",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "6b6d2c84"
      },
      "source": [
        "#### 85. Create a 2D array subclass such that Z[i,j] == Z[j,i] (★★★)"
      ],
      "id": "6b6d2c84"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "155e16ce"
      },
      "source": [
        ""
      ],
      "id": "155e16ce",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "7be0fe36"
      },
      "source": [
        "#### 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)) (★★★)"
      ],
      "id": "7be0fe36"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "ea732c23"
      },
      "source": [
        ""
      ],
      "id": "ea732c23",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "a840a88f"
      },
      "source": [
        "#### 87. Consider a 16x16 array, how to get the block-sum (block size is 4x4)? (★★★)"
      ],
      "id": "a840a88f"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "6e0c1cbe"
      },
      "source": [
        ""
      ],
      "id": "6e0c1cbe",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "c2bd7385"
      },
      "source": [
        "#### 88. How to implement the Game of Life using numpy arrays? (★★★)"
      ],
      "id": "c2bd7385"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "aea7d805"
      },
      "source": [
        ""
      ],
      "id": "aea7d805",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "4c70397b"
      },
      "source": [
        "#### 89. How to get the n largest values of an array (★★★)"
      ],
      "id": "4c70397b"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "16371718"
      },
      "source": [
        ""
      ],
      "id": "16371718",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "15ba193c"
      },
      "source": [
        "#### 90. Given an arbitrary number of vectors, build the cartesian product (every combinations of every item) (★★★)"
      ],
      "id": "15ba193c"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "c9c468d4"
      },
      "source": [
        ""
      ],
      "id": "c9c468d4",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "ec828405"
      },
      "source": [
        "#### 91. How to create a record array from a regular array? (★★★)"
      ],
      "id": "ec828405"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "84eb5fba"
      },
      "source": [
        ""
      ],
      "id": "84eb5fba",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "d94352b6"
      },
      "source": [
        "#### 92. Consider a large vector Z, compute Z to the power of 3 using 3 different methods (★★★)"
      ],
      "id": "d94352b6"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "301ba8a8"
      },
      "source": [
        ""
      ],
      "id": "301ba8a8",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "7c3a9e32"
      },
      "source": [
        "#### 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? (★★★)"
      ],
      "id": "7c3a9e32"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "777376e3"
      },
      "source": [
        ""
      ],
      "id": "777376e3",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "da9d5eeb"
      },
      "source": [
        "#### 94. Considering a 10x3 matrix, extract rows with unequal values (e.g. [2,2,3]) (★★★)"
      ],
      "id": "da9d5eeb"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "67dbea5c"
      },
      "source": [
        ""
      ],
      "id": "67dbea5c",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "f7b65fd5"
      },
      "source": [
        "#### 95. Convert a vector of ints into a matrix binary representation (★★★)"
      ],
      "id": "f7b65fd5"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "127294ed"
      },
      "source": [
        ""
      ],
      "id": "127294ed",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "2784c996"
      },
      "source": [
        "#### 96. Given a two dimensional array, how to extract unique rows? (★★★)"
      ],
      "id": "2784c996"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "f030595f"
      },
      "source": [
        ""
      ],
      "id": "f030595f",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "71a7574c"
      },
      "source": [
        "#### 97. Considering 2 vectors A & B, write the einsum equivalent of inner, outer, sum, and mul function (★★★)"
      ],
      "id": "71a7574c"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "721c4e1a"
      },
      "source": [
        ""
      ],
      "id": "721c4e1a",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "30f06441"
      },
      "source": [
        "#### 98. Considering a path described by two vectors (X,Y), how to sample it using equidistant samples (★★★)?"
      ],
      "id": "30f06441"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "fb41c022"
      },
      "source": [
        ""
      ],
      "id": "fb41c022",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "e5737276"
      },
      "source": [
        "#### 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. (★★★)"
      ],
      "id": "e5737276"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "68c333b0"
      },
      "source": [
        ""
      ],
      "id": "68c333b0",
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "5882e36d"
      },
      "source": [
        "#### 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). (★★★)"
      ],
      "id": "5882e36d"
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "d1b566e5"
      },
      "source": [
        ""
      ],
      "id": "d1b566e5",
      "execution_count": null,
      "outputs": []
    }
  ]
}