NumPy deg2rad() Function

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The NumPy deg2rad() function converts angles from degrees to radians. Radians are a standard unit of angular measurement in mathematics and science, and the relationship between degrees and radians is given by −

radians = degrees  ( / 180)

This function is particularly useful in trigonometric calculations where angles need to be in radians.

Syntax

Following is the syntax of the NumPy deg2rad() function −

numpy.deg2rad(x, out=None, where=True, casting='same_kind', order='K', dtype=None, subok=True)   

Parameters

Following are the parameters of the NumPy deg2rad() function −

• x: Input array. The elements represent angles in degrees and can be a NumPy array, list, or scalar value.
• out (optional): Alternate output array to place the result. It must have the same shape as the expected output.
• where(optional): A Boolean array. If True, compute the result; otherwise, it leaves the corresponding output elements unchanged.
• dtype(optional): Specifies the data type of the result.
• casting(optional): It ensures equivalent type conversion occurs. For example, converting from float32 to float64 is allowed, but converting from float64 to int32 is not.
• subok(optional)- It determines whether to subclass the output array if the data type is changed or to return a base-class array
• order (optional): It specifys the memory layout of the array. If object is not an array, the newly created array will be in C order (row major) unless F is specified, in which case it will be in Fortran order (column major) −
• 'C': C-style row-major order.
• 'F': Fortran-style column-major order.
• 'A': 'F' if the input is Fortran contiguous, 'C' otherwise.
• 'K': This is the default value keep the order as close as possible to the input.

Return Values

This function returns a NumPy array with the angles in radians corresponding to the input angles in degrees.

Example

Following is a basic example to convert angles in degrees to radians using the NumPy deg2rad() function −

import numpy as np  
# input array  
angles_in_degrees = np.array([0, 90, 180, 270, 360])  
# converting to radians  
angles_in_radians = np.deg2rad(angles_in_degrees)  
print("Radians:", angles_in_radians)  

Output

Following is the output of the above code −

Radians: [0.         1.57079633 3.14159265 4.71238898 6.28318531]  

Example: Scalar Input

The deg2rad() function also accepts a scalar input. In the following example, we have passed 180 as an argument to the deg2rad() function −

import numpy as np  
# scalar input  
degree = 180  
# converting to radians  
radian = np.deg2rad(degree)  
print("Radian for Scalar Input:", radian)  

Output

Following is the output of the above code −

Radian for Scalar Input: 3.141592653589793  

Example: Multi-dimensional Array

The deg2rad() function operates on multi-dimensional arrays. In the following example, we have created a 2X2 NumPy array with angles in degrees and converted them to radians −

import numpy as np  
# 2D array of angles in degrees  
angles_in_degrees = np.array([[0, 90], [180, 270]])  
# converting to radians  
angles_in_radians = np.deg2rad(angles_in_degrees)  
print("Radians for 2D Array:\n", angles_in_radians)  

Output

Following is the output of the above code −

Radians for 2D Array:  
[[0.         1.57079633]  
 [3.14159265 4.71238898]]  

Example: Plotting Conversion

In the following example, we have plotted the linear relationship between degrees and radians. To achieve this, we need to import the numpy and matplotlib.pyplot modules −

import numpy as np  
import matplotlib.pyplot as plt  

degrees = np.linspace(0, 360, 100)  # range of angles in degrees  
radians = np.deg2rad(degrees)  # converting to radians  

plt.plot(degrees, radians)  
plt.title("Degrees to Radians Conversion")  
plt.xlabel("Degrees")  
plt.ylabel("Radians")  
plt.grid()  
plt.show()