Quick Tutorial for Numpy Linspace with Examples for Beginners

What is Linspace() in Numpy

Numpy Linspace() function is used to create a numpy array with evenly spaced numbers between the two intervals provided as input.  In this tutorial, we will see the syntax of np.linspace() and see various examples by using various parameters.

Numpy Linspace: np.linspace()

Syntax

np.linspace(start, stop, num=50, endpoint=True, retstep=False, dtype=None, axis=0)

• start – This signifies the starting value of the sequence and can be a number or an array-like value.
• stop – This signifies the stop value of the sequence and can be a number or any array-like value. However, when the endpoint is False the stop value is excluded from the sequence.
• num (optional) – It denotes the number of samples to be generated between the start and stop. The input should be of int type and non-negative. The default value is 50.
• endpoint (optional) – When its True, the last value mentioned in the stop is included otherwise not included when False. The default value is True.
• retstep (optional) – When True the function also returns the step size used to generate the sequence of samples. The default value is False.
• dtype (optional) – It denotes the data type of the numpy array that is returned as the output. If it is not mentioned, then it will infer from the start and stop parameters. However, it should be noted that even though start and stop are integers, the output numpy array will be of type float only.
• axis (optional) – It denotes the axis in the result to store the samples and is relevant only when start or stop values are array-like. The default value is 0, where samples are along a new axis inserted at the beginning. -1 is used to have the axis at the end.

Examples of Numpy Linspace

Import Numpy Library

Before going into the examples, let us first import the numpy library as below.

In [0]:

import numpy as np

Example 1 – Simple Example of Numpy Linspace

Let us begin with the simplest example where we are using only start and stop parameters in np.linspace function.

In this example, the start =1 and stop=10 are passed, and a 1-D numpy array is generated consisting of 50 evenly spaced numbers. (Do remember that when the parameter num is not used, it produces an array of 50 elements by default.)

In [1]:

arr = np.linspace(start = 1, stop = 10);

print(arr)

Out[1]:

[ 1.          1.18367347  1.36734694  1.55102041  1.73469388  1.91836735
  2.10204082  2.28571429  2.46938776  2.65306122  2.83673469  3.02040816
  3.20408163  3.3877551   3.57142857  3.75510204  3.93877551  4.12244898
  4.30612245  4.48979592  4.67346939  4.85714286  5.04081633  5.2244898
  5.40816327  5.59183673  5.7755102   5.95918367  6.14285714  6.32653061
  6.51020408  6.69387755  6.87755102  7.06122449  7.24489796  7.42857143
  7.6122449   7.79591837  7.97959184  8.16326531  8.34693878  8.53061224
  8.71428571  8.89795918  9.08163265  9.26530612  9.44897959  9.63265306
  9.81632653 10.        ]

Example 2 – Using Num Parameter

The num parameter is used to denote that how many elements would be there in the numpy array. In the below example, num=4 is passed and the output numpy array contains only 4 elements between 0 and 24.

In [2]:

arr = np.linspace(start = 0, stop = 24, num=4);

print(arr)

[ 0.,  8., 16., 24.]

arr = np.linspace(start = 0, stop = 24, num=4, dtype=int);

print(arr)

[ 0 8 16 24]

Example 4 – Using endpoint in np.linspace

arr = np.linspace(start = 0, stop = 24, num=4, endpoint=False, dtype=int);

print(arr)

Out[4]:

[ 0 6 12 18]

Example 5 – Using retstep Parameter

arr = np.linspace(start = 0, stop = 24, num=4, endpoint=False, dtype=int, retstep=True);

print(arr)

(array([ 0, 6, 12, 18]), 6.0)

To create the 2-D numpy array with linspace you can use a vector of numbers in either start or stop or both the parameters as shown in the below examples

In [6]:

arr = np.linspace(start = (3,9), stop = 24, num=4,dtype=int);

print(arr)

[[ 3  9]
 [10 14]
 [17 19]
 [24 24]]

In [7]:

arr = np.linspace(start = (3,9), stop = (24,48), num=4,dtype=int);

print(arr)

[[ 3  9]
 [10 22]
 [17 35]
 [24 48]]

In [8]:

arr = np.linspace(start = 9, stop = (24,48), num=4,dtype=int);

print(arr)

[[ 9  9]
 [14 22]
 [19 35]
 [24 48]]

Reference – Numpy Documentation