Understanding Python numpy.linspace()

The numpy.linspace() function is a useful tool in the NumPy library for generating arrays of evenly spaced numbers over a specified range. It is particularly helpful in data visualization and scientific calculations. This guide will explain how to use numpy.linspace() effectively with examples.

What is numpy.linspace()?

The numpy.linspace() function creates an array of numbers between a specified start and stop value. It evenly spaces the numbers across the range. The syntax is:

numpy.linspace(start, stop, num=50, endpoint=True, retstep=False, dtype=None)

It allows you to define the number of elements, whether to include the endpoint, and other optional parameters.

Prerequisites

Before using numpy.linspace(), make sure you have NumPy installed. If not, follow our guide: How to Install NumPy in Python.

If you encounter a ModuleNotFoundError: No module named 'numpy', check out this solution: [Solved] ModuleNotFoundError: No module named 'numpy'.

Basic Usage of numpy.linspace()

Here is a simple example of using numpy.linspace() to create an array of 10 evenly spaced numbers between 0 and 1:

import numpy as np

# Create an array of 10 values from 0 to 1
arr = np.linspace(0, 1, num=10)
print(arr)

Output:
[0.         0.11111111 0.22222222 0.33333333 0.44444444 0.55555556
 0.66666667 0.77777778 0.88888889 1.        ]

This generates 10 values evenly spaced between 0 and 1.

Including or Excluding the Endpoint

The endpoint parameter in numpy.linspace() determines if the stop value is included. By default, it is set to True. Here is an example with endpoint=False:

# Create an array with endpoint excluded
arr_no_endpoint = np.linspace(0, 1, num=5, endpoint=False)
print(arr_no_endpoint)

Output:
[0.  0.2 0.4 0.6 0.8]

This example generates an array with 5 values where 1 is not included as the endpoint.

Returning the Step Size

The retstep parameter allows you to return the step size between the numbers in the array:

# Get the array and step size
arr, step = np.linspace(0, 1, num=5, retstep=True)
print("Array:", arr)
print("Step size:", step)

Output:
Array: [0.   0.25 0.5  0.75 1.  ]
Step size: 0.25

This feature is helpful when you need to know the exact spacing between values.

Difference Between numpy.linspace() and numpy.arange()

Both numpy.linspace() and numpy.arange() are used to generate sequences of numbers, but they have different use cases. numpy.linspace() is preferred when you want to specify the number of elements directly. On the other hand, numpy.arange() is useful when you need to define the step size. For more details, check out our article on Understanding Python numpy.arange().

Conclusion

The numpy.linspace() function is a versatile tool for generating sequences of numbers with precise control over the number of elements. Whether you are plotting graphs or working with mathematical data, numpy.linspace() simplifies the process of generating evenly spaced arrays. Understanding this function will help you work more efficiently with numerical data in Python.