NumPy, short for Numerical Python, is one of the fundamental libraries for numerical computing in Python. It provides support for large, multi-dimensional arrays and matrices, along with a collection of mathematical functions to operate on these arrays efficiently. NumPy is widely used in scientific computing, data analysis, and machine learning due to its powerful array manipulation capabilities.

Getting Started

If numpy is not installed on your system, then install it usingthe following command.

!pip install numpy

Before using NumPy, you need to import it into your Python script or interactive session:

import numpy as np

Now, let’s explore some of the essential modules and functions provided by NumPy:

Creating Arrays

NumPy arrays can be created using various methods. Here are some common ones:

np.array(): Create an array from a Python list or tuple.

arr = np.array([1, 2, 3, 4, 5])
print(arr)

np.zeros(): Create an array filled with zeros.

zeros_arr = np.zeros((2, 3))  # 2 rows, 3 columns
print(zeros_arr)

np.ones(): Create an array filled with ones.

ones_arr = np.ones((3, 2))  # 3 rows, 2 columns
print(ones_arr)

np.arange(): Create an array with a range of values.

range_arr = np.arange(0, 10, 2)  # start, stop, step
print(range_arr)

np.linspace(): Create an array with evenly spaced values over a specified range.

linspace_arr = np.linspace(0, 5, 10)  # start, stop, num
print(linspace_arr)

Array Attributes

NumPy arrays have several attributes that provide information about the array:

ndim: Number of dimensions (axes) of the array.

print(arr.ndim)

shape: Tuple indicating the size of each dimension.

print(arr.shape)

size: Total number of elements in the array.

print(arr.size)

dtype: Data type of the array elements.

print(arr.dtype)

Array Operations

NumPy allows various operations on arrays, including element-wise operations, mathematical functions, and linear algebra operations:

Element-wise Operations: NumPy supports arithmetic operations between arrays of the same shape.

arr1 = np.array([1, 2, 3])
arr2 = np.array([4, 5, 6])

sum_arr = arr1 + arr2
print(sum_arr)

Mathematical Functions: NumPy provides many mathematical functions that can be applied element-wise to arrays.

arr = np.array([1, 2, 3])

# Square root of each element
sqrt_arr = np.sqrt(arr)
print(sqrt_arr)

Linear Algebra Operations: NumPy provides functions for linear algebra operations, such as matrix multiplication and determinant calculation.

matrix1 = np.array([[1, 2], [3, 4]])
matrix2 = np.array([[5, 6], [7, 8]])

# Matrix multiplication
matrix_product = np.dot(matrix1, matrix2)
print(matrix_product)

Indexing and Slicing

NumPy arrays support indexing and slicing operations to access elements or subarrays:

arr = np.array([1, 2, 3, 4, 5])

# Accessing individual elements
print(arr[0])   # First element
print(arr[-1])  # Last element

# Slicing
print(arr[1:4])  # Elements from index 1 (inclusive) to 4 ()

NumPy is a powerful library for numerical computing in Python. In this tutorial, we’ve covered the basics of NumPy, including creating arrays, array attributes, array operations, indexing, and slicing. With NumPy, you can efficiently manipulate large datasets and perform complex mathematical operations, making it an essential tool for data science and scientific computing.