NumPy Tutorial NumPy Statistics NumPy References

NumPy - extract() function

The NumPy extract() function returns the elements of an array that satisfy some condition. If condition is boolean the function is equivalent to arr[condition].


numpy.extract(condition, arr)


condition Required. Specify an array whose nonzero or True entries indicate the elements of arr to extract.
arr Required. Specify the array (array_like) of the same size as condition.

Return Value

Returns Rank 1 array of values from arr where condition is True.


In the example below, extract() function is used to extract elements from an array based on given condition.

import numpy as np

Arr = np.arange(12).reshape((3, 4))

#displaying the array
print("The original array:")

#defining condition
condition = np.mod(Arr, 3) == 0
print("\nCondition is:")

#applying condition on array
print("\nExtracting elements based on condition:")
print(np.extract(condition, Arr))

The output of the above code will be:

The original array:
[[ 0  1  2  3]
 [ 4  5  6  7]
 [ 8  9 10 11]]

Condition is:
[[ True False False  True]
 [False False  True False]
 [False  True False False]]

Extracting elements based on condition:
[0 3 6 9]

❮ NumPy - Functions