Use NumPy extract() or Where() function to filter array by condition.
NumPy filter array by condition example
Simple example code NumPy filter using condition on each element.
Using NumPy.extract:
import numpy as np
na = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
res = np.extract(na % 2 == 0, na)
print(res)
Output:
Using NumPy.where:
import numpy as np
na = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
res = na[np.where(na % 2 == 0)]
print(res)
Output: [ 2 4 6 8 10]
How to efficiently filter elements in a NumPy array by value in Python?
Answer: Use boolean indexing to filter elements in an array by value to filter NumPy Array.
import numpy as np
na = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
res = na[na > 4]
print(res)Output: [ 5 6 7 8 9 10]
Do comment if you have any doubts or suggestions on this NumPy Array topic.
Note: IDE: PyCharm 2021.3.3 (Community Edition)
Windows 10
Python 3.10.1
All Python Examples are in Python 3, so Maybe its different from python 2 or upgraded versions.