Published Jun 25, 2024
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In NumPy, the .sin() method calculates the trigonometric sine of each element in an array. This method operates element-wise on an array and returns a new array containing the sine values of the input array’s elements. It is beneficial in mathematical computations involving trigonometric operations.


numpy.sin(x, out=None, where=True)
  • array: An array-like structure containing the elements for which the sine is computed. The elements should be in radians, not degrees.
  • out (Optional): Specifies the array where the result of the operation should be stored. If not provided, a new array is created to store the results.
  • where (Optional): The condition (array of boolean values) that determines the elements where the sine function is applied.
    • If the condition is True for a particular element, the sine is computed for that element.
    • If the condition is False for a particular element, the sine of the element will not be computed and the original element is retained.
    • If not provided, the sine is computed for all elements.


The following example illustrates the usage of the .sin() method:

# Importing the 'numpy' library as 'np'
import numpy as np
# When the elements in the array are already in radians
array1 = np.array([0, np.pi/2, np.pi, 3*np.pi/2])
result1 = np.sin(array1)
# The angles are originally in degrees, so they need to be converted to radians
array2 = np.array((0, 30, 45, 90, 180))
result2 = np.sin(array2 * np.pi/180) # convert to radians
# using the where parameter
array3 = np.array([np.pi/6, np.pi/4, np.pi/2, np.pi])
result3 = np.sin(array3, where=array3 >= np.pi/2)

The output of the above code is as shown below:

[ 0.0000000e+00 1.0000000e+00 1.2246468e-16 -1.0000000e+00]
[0.00000000e+00 5.00000000e-01 7.07106781e-01 1.00000000e+00
[0.0000000e+00 0.0000000e+00 1.0000000e+00 1.2246468e-16]

Codebyte Example

In this codebyte example, the .sin() method computes the sine of the elements of the array:


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