NumPy arcsin()

import numpy as np

# create an array of values between -1 and 1
values = np.array([-1, -0.5, 0, 0.5, 1])

# calculate the inverse sine of each value
inverseSine = np.arcsin(values)

print(inverseSine)

# Output: [-1.57079633 -0.52359878  0.          0.52359878  1.57079633]

arcsin() Syntax

The syntax of arcsin() is:

numpy.arcsin(x, out=None, where = True, dtype = None)

arcsin() Arguments

The arcsin() method takes following arguments:

• x - an input array
• out (optional) - the output array where the result will be stored
• where (optional) - a boolean array or condition indicating where to compute the arcsine
• dtype (optional) - data type of the output array

arcsin() Return Value

The arcsin() method returns an array with the corresponding inverse sine values.

Example 1: Use of out and where in arcsin()

import numpy as np

# create an array of values between -0.5 and 0.5
values = np.array([-0.5, -0.2, 1, 0.2, 0.5])

# create an array of zeros with the same shape as values
result = np.zeros_like(values, dtype=float)  

# calculate inverse sine where values >= 0 and store in result.
np.arcsin(values, out=result, where=(values >= 0))

print(result)

Output

[0.         0.         1.57079633 0.20135792 0.52359878]

Here,

• out=result specifies that the output of the np.arcsin() function should be stored in the result array
• where=(values >= 0) specifies that the inverse sine operation should only be applied to elements in values that are greater than or equal to 0

Example 2: Use of dtype Argument in arcsin()

import numpy as np

# create an array of values between -0.5 and 0.5
values = np.array([-0.5, -0.2, 0, 0.2, 0.5])

# calculate the inverse sine of each value with a specific dtype
inverse_sines_float = np.arcsin(values, dtype=float)
inverse_sines_complex = np.arcsin(values, dtype=complex)

print("Inverse sines with 'float' dtype:")
print(inverse_sines_float)

print("\nInverse sines with 'complex' dtype:")
print(inverse_sines_complex)

Output

Inverse sines with 'float' dtype:
[-0.52359878 -0.20135792  0.          0.20135792  0.52359878]

Inverse sines with 'complex' dtype:
[-0.52359878+0.j -0.20135792+0.j  0.        +0.j  0.20135792+0.j
  0.52359878+0.j]

Here, by specifying the desired dtype, we can control the data type of the output array according to our requirements.

Note: To learn more about the dtype argument, please visit NumPy Data Types.