Gavin Wiggins

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Boolean indexing

Written on November 7, 2022

Use boolean indexing in NumPy arrays to assign values. The example below assigns a zero to array items that are less than zero.

>>> import numpy as np
>>> nums = np.array([-1, 3, 6, -0.2, -4])
>>> nums[nums < 0] = 0
>>> nums
array([0., 3., 6., 0., 0.])