Tutorial 8- Python Numpy Arrays .ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "id": "a6ee34e0",
   "metadata": {},
   "source": [
    "## Tutorial 8-Python Numpy Arrays "
   ]
  },
  {
   "cell_type": "markdown",
   "id": "332fa60e",
   "metadata": {},
   "source": [
    "## Numpy Tutorials\n",
    "NumPy is a general-purpose array-processing package. It provides a high-performance multidimensional array object, and tools for working with these arrays. It is the fundamental package for scientific computing with Python"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "07522d00",
   "metadata": {},
   "source": [
    "## What is an array\n",
    "An array is a data structure that stores values of same data type. In Python, this is the main difference between arrays and lists. While python lists can contain values corresponding to different data types, arrays in python can only contain values corresponding to same data type"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "id": "b185b2c6",
   "metadata": {},
   "outputs": [],
   "source": [
    "## import the library\n",
    "import numpy as np"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "id": "bb1b5a35",
   "metadata": {},
   "outputs": [],
   "source": [
    "lst=[1,2,3,4]\n",
    "arr=np.array(lst)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "id": "1f8d70bb",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "numpy.ndarray"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "type(arr)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "id": "d145b60f",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(4,)"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr.shape"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "id": "d6f716b0",
   "metadata": {},
   "outputs": [],
   "source": [
    "lst1=[1,2,3,4,5]\n",
    "lst2=[2,3,4,5,6]\n",
    "lst3=[3,4,5,6,7]\n",
    "\n",
    "arr1=np.array([lst1,lst2,lst3])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "id": "a81d1013",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[1, 2, 3, 4, 5],\n",
       "       [2, 3, 4, 5, 6],\n",
       "       [3, 4, 5, 6, 7]])"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "id": "71f2ad15",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(3, 5)"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr1.shape"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "id": "23550f22",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([1, 2, 3, 4])"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "id": "a6090742",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "4"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#indexing\n",
    "arr[3]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "id": "17b36e76",
   "metadata": {},
   "outputs": [],
   "source": [
    "arr[3]=5"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "id": "55144bda",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([1, 2, 3, 5])"
      ]
     },
     "execution_count": 14,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "id": "549a9c41",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr[-1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "id": "86917975",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([1, 2, 3])"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr[:-1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "id": "6944a7ac",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([5, 1])"
      ]
     },
     "execution_count": 25,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr[::-3]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "id": "c45419ad",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[1, 2, 3, 4, 5],\n",
       "       [2, 3, 4, 5, 6],\n",
       "       [3, 4, 5, 6, 7]])"
      ]
     },
     "execution_count": 26,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 32,
   "id": "2cdcf9f7",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(3, 2)"
      ]
     },
     "execution_count": 32,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr1[:,3:].shape"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "id": "5b67e1e5",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([2, 3, 4])"
      ]
     },
     "execution_count": 28,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr1[:,1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "id": "59aab9ee",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[3, 4],\n",
       "       [4, 5]])"
      ]
     },
     "execution_count": 29,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr1[1:,1:3]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 30,
   "id": "060e8f8b",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[5, 6],\n",
       "       [6, 7]])"
      ]
     },
     "execution_count": 30,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr1[1:,3:]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 33,
   "id": "a515ea9c",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([1, 2, 3, 5])"
      ]
     },
     "execution_count": 33,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "##EDA\n",
    "arr"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 35,
   "id": "55a75b02",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([1])"
      ]
     },
     "execution_count": 35,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr[arr<2]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 37,
   "id": "c9584f93",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[1, 2, 3, 4, 5],\n",
       "       [2, 3, 4, 5, 6],\n",
       "       [3, 4, 5, 6, 7]])"
      ]
     },
     "execution_count": 37,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 40,
   "id": "6d6d0a24",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[1, 2, 3],\n",
       "       [4, 5, 2],\n",
       "       [3, 4, 5],\n",
       "       [6, 3, 4],\n",
       "       [5, 6, 7]])"
      ]
     },
     "execution_count": 40,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr1.reshape(5,3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 44,
   "id": "d1462081",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[ 1,  3,  5,  7,  9],\n",
       "       [11, 13, 15, 17, 19]])"
      ]
     },
     "execution_count": 44,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "##mechanism to create an array\n",
    "np.arange(1,20,2).reshape(2,5)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 47,
   "id": "ce3eada1",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[[ 1],\n",
       "        [ 3],\n",
       "        [ 5],\n",
       "        [ 7],\n",
       "        [ 9]],\n",
       "\n",
       "       [[11],\n",
       "        [13],\n",
       "        [15],\n",
       "        [17],\n",
       "        [19]]])"
      ]
     },
     "execution_count": 47,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "np.arange(1,20,2).reshape(2,5,1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 49,
   "id": "be8061d2",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([ 1,  4,  9, 25])"
      ]
     },
     "execution_count": 49,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr *arr"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 52,
   "id": "558ee842",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[ 1,  4,  9, 16, 25],\n",
       "       [ 4,  9, 16, 25, 36],\n",
       "       [ 9, 16, 25, 36, 49]])"
      ]
     },
     "execution_count": 52,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr1 * arr1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 53,
   "id": "bbe15cc2",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[1., 1., 1.],\n",
       "       [1., 1., 1.],\n",
       "       [1., 1., 1.],\n",
       "       [1., 1., 1.],\n",
       "       [1., 1., 1.]])"
      ]
     },
     "execution_count": 53,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "np.ones((5,3))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 54,
   "id": "6533e57a",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[0., 0., 0., 0., 0.],\n",
       "       [0., 0., 0., 0., 0.],\n",
       "       [0., 0., 0., 0., 0.],\n",
       "       [0., 0., 0., 0., 0.]])"
      ]
     },
     "execution_count": 54,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "np.zeros((4,5))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 78,
   "id": "b69c75d0",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[42, 24],\n",
       "       [42, 27]])"
      ]
     },
     "execution_count": 78,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "np.random.randint(10,50,4).reshape(2,2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 79,
   "id": "1c57dfae",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[-1.81506768, -0.18073426,  1.50531807,  0.04701715,  0.00345232,\n",
       "        -1.89048526],\n",
       "       [-1.19316745, -0.8222509 , -0.11386853, -1.47422866,  2.28291196,\n",
       "         0.02731563],\n",
       "       [ 0.4027173 ,  0.02478252, -1.44510603, -0.99842738, -0.07634666,\n",
       "        -0.81335324],\n",
       "       [ 0.9692424 ,  1.41109806, -0.33335031,  1.18717669,  0.59522992,\n",
       "         0.88923165],\n",
       "       [ 1.10478558, -0.44639422,  0.06939313,  0.64813885,  0.54669759,\n",
       "        -0.19369955]])"
      ]
     },
     "execution_count": 79,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "np.random.randn(5,6)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 80,
   "id": "c4e377f7",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[0.13871895, 0.58456466, 0.31541441, 0.67910295, 0.1837086 ,\n",
       "        0.08103746, 0.50976945],\n",
       "       [0.67483078, 0.41252643, 0.0877961 , 0.92338101, 0.25762097,\n",
       "        0.55850649, 0.26534539],\n",
       "       [0.05930126, 0.53209293, 0.90407746, 0.71743787, 0.89905166,\n",
       "        0.22360872, 0.10365036],\n",
       "       [0.36820358, 0.30483507, 0.49569278, 0.7850211 , 0.96484935,\n",
       "        0.72614993, 0.83010606]])"
      ]
     },
     "execution_count": 80,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "np.random.random_sample((4,7))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "b1db7481",
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 3 (ipykernel)",
   "language": "python",
   "name": "python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.9.7"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 5
}