NumPy deg2rad() – Convert Degrees to Radians

NumPy deg2rad()

The numpy.deg2rad() function converts angles from degrees to radians. This is useful when working with trigonometric functions, which typically require angles in radians.

Syntax

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

Parameters

Parameter	Type	Description
x	array_like	Angles in degrees to be converted into radians.
out	ndarray, None, or tuple of ndarray and None, optional	Optional output array where the result is stored. If None, a new array is created.
where	array_like, optional	Boolean mask specifying which elements to convert. Elements where where=False retain their original value.
casting	str, optional	Defines the casting behavior when converting degrees to radians.
order	str, optional	Memory layout order of the output array.
dtype	data-type, optional	Defines the data type of the output array.
subok	bool, optional	Determines if subclasses of ndarray are preserved in the output.

Return Value

Returns an array with the converted angles in radians. If the input is a scalar, a scalar is returned.

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Examples

1. Converting a Single Angle from Degrees to Radians

Here, we convert 180 degrees to radians.

import numpy as np

# Define an angle in degrees
angle_deg = 180

# Convert the angle to radians
angle_rad = np.deg2rad(angle_deg)

# Print the result
print("180 degrees in radians:", angle_rad)

Output:

180 degrees in radians: 3.141592653589793

2. Converting an Array of Angles

We convert an array of degree values to radians.

import numpy as np

# Define an array of angles in degrees
angles_deg = np.array([0, 30, 45, 60, 90, 180, 270, 360])

# Convert the angles to radians
angles_rad = np.deg2rad(angles_deg)

# Print the results
print("Angles in degrees:", angles_deg)
print("Converted angles in radians:", angles_rad)

Output:

Angles in degrees: [  0  30  45  60  90 180 270 360]
Converted angles in radians: [0.         0.52359878 0.78539816 1.04719755 1.57079633 3.14159265
 4.71238898 6.28318531]

3. Using the out Parameter

Using an output array to store the converted values.

import numpy as np

# Define an array of angles
angles_deg = np.array([0, 45, 90, 180])

# Create an output array with the same shape
output_array = np.empty_like(angles_deg, dtype=np.float64)

# Convert degrees to radians and store the result in output_array
np.deg2rad(angles_deg, out=output_array)

# Print the results
print("Converted radians stored in output array:", output_array)

Output:

Converted radians stored in output array: [0.         0.78539816 1.57079633 3.14159265]

4. Using the where Parameter

Using a condition to convert only selected angles.

import numpy as np

# Define an array of angles
angles_deg = np.array([0, 45, 90, 180])

# Define a mask (convert only where mask is True)
mask = np.array([True, False, True, False])

# Convert only selected angles
result = np.deg2rad(angles_deg, where=mask)

# Print the results
print("Converted radians with mask:", result)

Output:

Converted radians with mask: [0.         0.         1.57079633 0.        ]

The conversion is applied only to elements where mask=True.