01 - Numpy.ipynb

{
  "nbformat": 4,
  "nbformat_minor": 0,
  "metadata": {
    "colab": {
      "name": "01 - Numpy.ipynb",
      "version": "0.3.2",
      "provenance": []
    },
    "language_info": {
      "codemirror_mode": {
        "name": "ipython",
        "version": 3
      },
      "file_extension": ".py",
      "mimetype": "text/x-python",
      "name": "python",
      "nbconvert_exporter": "python",
      "pygments_lexer": "ipython3",
      "version": "3.7.3"
    },
    "kernelspec": {
      "display_name": "Python 3",
      "language": "python",
      "name": "python3"
    }
  },
  "cells": [
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "62n36YEXepbr",
        "colab_type": "text"
      },
      "source": [
        "# Numpy\n",
        "\n",
        "- provides more functionality to work with multi dimensional arrays\n",
        "- much more convenient in terms of helper functions as well as syntax"
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "WzSravDYepbt",
        "colab_type": "code",
        "colab": {}
      },
      "source": [
        "import numpy as np"
      ],
      "execution_count": 0,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "PwBnlagYepbx",
        "colab_type": "text"
      },
      "source": [
        "The simplest way to get started with Numpy is to create an array. This can be done by invoking the array method in numpy and passing it an argument. This may be a list or a tuple or a set"
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "vG052fu5epby",
        "colab_type": "code",
        "outputId": "f58fb360-1c71-4602-fba5-6af278937bc6",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 34
        }
      },
      "source": [
        "np.array([1,2,3,4])\n"
      ],
      "execution_count": 3,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "array([1, 2, 3, 4])"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 3
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "qX0_ILSeepb3",
        "colab_type": "code",
        "outputId": "3ec2ade9-8f80-41b7-e2f2-37e2eae812b0",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 34
        }
      },
      "source": [
        "np.array((1,2,3,4))"
      ],
      "execution_count": 4,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "array([1, 2, 3, 4])"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 4
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "5_iBiWbcepb7",
        "colab_type": "code",
        "outputId": "3a6ae8ef-8ee6-477f-e301-91efb17e174c",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 34
        }
      },
      "source": [
        "np.array(set([1,2,3,4]))"
      ],
      "execution_count": 5,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "array({1, 2, 3, 4}, dtype=object)"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 5
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "VVJuSDrQepb-",
        "colab_type": "code",
        "outputId": "ee0e68c0-c9a5-4321-9dbb-58eeb361cd0b",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 34
        }
      },
      "source": [
        "set([1,2,3, 4, 4])"
      ],
      "execution_count": 6,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "{1, 2, 3, 4}"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 6
        }
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "U2RXVLu6epcD",
        "colab_type": "text"
      },
      "source": [
        "To create an array from 0 to n-1 we use the range function in normal python"
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "ig66MaLVepcG",
        "colab_type": "code",
        "outputId": "401fa1b0-5877-4909-fb3c-07f51113f7d6",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 34
        }
      },
      "source": [
        "list(range(10))"
      ],
      "execution_count": 7,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 7
        }
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "WXcNw56ve-LC",
        "colab_type": "text"
      },
      "source": [
        "However in numpy we use the `np.arange` function"
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "kzUzhc7fepcK",
        "colab_type": "code",
        "outputId": "5358befb-e500-4a26-83a9-a62e8f4a57bc",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 34
        }
      },
      "source": [
        "np.arange(10)"
      ],
      "execution_count": 8,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 8
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "cf2wMBw0mpOp",
        "colab_type": "code",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 34
        },
        "outputId": "9923fbb7-a9ab-4b78-957b-2561cc911847"
      },
      "source": [
        "arr = np.array([1,2,3,4])\n",
        "arr + 1"
      ],
      "execution_count": 12,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "array([2, 3, 4, 5])"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 12
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "OdDftpGenBt9",
        "colab_type": "code",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 34
        },
        "outputId": "5440f421-091c-4f7e-f6a8-4474854a3596"
      },
      "source": [
        "b = np.ones(4) + 1\n",
        "c = np.ones(4)\n",
        "\n",
        "b+c"
      ],
      "execution_count": 14,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "array([3., 3., 3., 3.])"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 14
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "IzSAsUgsnYtf",
        "colab_type": "code",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 34
        },
        "outputId": "d61a0f02-520d-433d-85e1-6bb8f7865ea0"
      },
      "source": [
        "b * (c + 4)"
      ],
      "execution_count": 16,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "array([10., 10., 10., 10.])"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 16
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "CP3DgA5WndUc",
        "colab_type": "code",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 85
        },
        "outputId": "d6e8cfe4-c371-4ad8-8f31-f73e1b050082"
      },
      "source": [
        "d = np.diag([1,2,3,4])\n",
        "d * d"
      ],
      "execution_count": 19,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "array([[ 1,  0,  0,  0],\n",
              "       [ 0,  4,  0,  0],\n",
              "       [ 0,  0,  9,  0],\n",
              "       [ 0,  0,  0, 16]])"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 19
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "3TwUrUYAntOF",
        "colab_type": "code",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 85
        },
        "outputId": "0f0a56d0-c3e0-41db-f18c-8035b83648d8"
      },
      "source": [
        "(np.eye(4) * 2).dot(np.diag([1,2,3,4]))"
      ],
      "execution_count": 25,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "array([[2., 0., 0., 0.],\n",
              "       [0., 4., 0., 0.],\n",
              "       [0., 0., 6., 0.],\n",
              "       [0., 0., 0., 8.]])"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 25
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "j1R5JZxroLkE",
        "colab_type": "code",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 51
        },
        "outputId": "c38e8869-8d46-49fe-b61e-c359615ea431"
      },
      "source": [
        "np.array([[1,2,3],[4, 5, 6]]).dot(np.array([[1,2],[3,4], [5, 6]]))"
      ],
      "execution_count": 31,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "array([[22, 28],\n",
              "       [49, 64]])"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 31
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "QJOTqzODocPb",
        "colab_type": "code",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 51
        },
        "outputId": "f48736d8-70ad-4ca4-84ed-1c129465c54a"
      },
      "source": [
        "np.array([[1,2,3],[4, 5, 6]]) * np.array([[1,2,3],[4, 5, 7]])"
      ],
      "execution_count": 36,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "array([[ 1,  4,  9],\n",
              "       [16, 25, 42]])"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 36
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "G4WVgBOmo7TK",
        "colab_type": "code",
        "colab": {}
      },
      "source": [
        "# normal operations using np objects are scalar operations on all elements"
      ],
      "execution_count": 0,
      "outputs": []
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "LsTHRGf4o_Q2",
        "colab_type": "code",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 34
        },
        "outputId": "e08995e4-1352-4da2-a3f1-9f8207db9f46"
      },
      "source": [
        "np.sum(b)"
      ],
      "execution_count": 39,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "8.0"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 39
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "oZEQ-bCxpmhb",
        "colab_type": "code",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 34
        },
        "outputId": "4b5460b3-4b61-4b7b-ac77-f3bb741d5fc0"
      },
      "source": [
        "np.max(d)"
      ],
      "execution_count": 47,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "4"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 47
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "ehKXJ7NwpqjN",
        "colab_type": "code",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 34
        },
        "outputId": "6e441566-a126-4d38-ceb7-e1881321ebc3"
      },
      "source": [
        "np.argmax(d)"
      ],
      "execution_count": 48,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "15"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 48
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "zRcqcjTBprqI",
        "colab_type": "code",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 85
        },
        "outputId": "91f81178-faed-46e1-f612-5bb3ad42fe63"
      },
      "source": [
        "d"
      ],
      "execution_count": 46,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "array([[1, 0, 0, 0],\n",
              "       [0, 2, 0, 0],\n",
              "       [0, 0, 3, 0],\n",
              "       [0, 0, 0, 4]])"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 46
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "5ny3s2pVpsDk",
        "colab_type": "code",
        "colab": {}
      },
      "source": [
        ""
      ],
      "execution_count": 0,
      "outputs": []
    }
  ]
}