# Python Numpy.sqrt() - Square Root

Jinku Hu Jan 30, 2023

`Numpy.sqrt()` function calculates the square root of every element in the given array.

It is the inverse operation of `Numpy.square()` method.

## Syntax of `numpy.sqrt()`

``````numpy.sqrt(arr, out=None)
``````

### Parameters

`arr` input array
`out` If `out` is given, the result will be stored in `out`. `out` should have the same shape as `arr`.

### Return

It returns an array of the square root of each element in the input array, even if `out` is given.

## Example Codes: `numpy.sqrt()`

``````import numpy as np

arr = [1, 9, 25, 49]

arr_sqrt = np.sqrt(arr)

print(arr_sqrt)
``````

Output:

``````[1. 3. 5. 7.]
``````

## Example Codes: `numpy.sqrt()` With `out` Parameter

``````import numpy as np

arr = [1, 9, 25, 49]
out_arr = np.zeros(4)

arr_sqrt = np.sqrt(arr, out_arr)

print(out_arr)
print(arr_sqrt)
``````

Output:

``````[1. 3. 5. 7.]
[1. 3. 5. 7.]
``````

`out_arr` has the same shape as `arr`, and the square root of `arr` is saved in it. And the `numpy.sqrt()` method also returns the square root array, as shown above.

If `out` doesn’t have the same shape as `arr`, it raises a `ValueError`.

``````import numpy as np

arr = [1, 9, 25, 49]
out_arr = np.zeros((2, 2))

arr_sqrt = np.sqrt(arr, out_arr)

print(out_arr)
print(arr_sqrt)
``````

Output:

``````Traceback (most recent call last):
File "C:\Test\test.py", line 6, in <module>
arr_sqrt = np.sqrt(arr, out_arr)
ValueError: operands could not be broadcast together with shapes (4,) (2,2)
``````

## Example Codes: `numpy.sqrt()` With Negative Numbers

``````import numpy as np

arr = [-1, -9, -25, -49]

arr_sqrt = np.sqrt(arr)

print(arr_sqrt)
``````

Output:

``````Warning (from warnings module):
File "..\test.py", line 5
arr_sqrt = np.sqrt(arr)
RuntimeWarning: invalid value encountered in sqrt
[nan nan nan nan]
``````

It throws a `RuntimeWarning` when the input is a negative number and returns `nan` as a result.

## Example Codes: `numpy.sqrt()` With Complex Numbers

``````import numpy as np

arr = [3 + 4j, -5 + 12j, 8 - 6j, -15 - 8j]

arr_sqrt = np.sqrt(arr)

print(arr_sqrt)
``````

Output:

``````[2.+1.j 2.+3.j 3.-1.j 1.-4.j]
``````

A complex number has two square roots. For example,

`numpy.sqrt()` method returns only one square root, which has a positive real number.

Author: Jinku Hu

Founder of DelftStack.com. Jinku has worked in the robotics and automotive industries for over 8 years. He sharpened his coding skills when he needed to do the automatic testing, data collection from remote servers and report creation from the endurance test. He is from an electrical/electronics engineering background but has expanded his interest to embedded electronics, embedded programming and front-/back-end programming.