Python numpy.extract()

The numpy.extract()函数返回input_array的元素，如果它们满足某些指定的条件。

语法: numpy.extract(condition, array)

参数 :

array : 输入数组。用户在input_array元素上应用条件
condition : [array_like]条件，用户在此基础上提取元素。在input_array上应用条件，如果我们打印条件，它将返回一个数组充满True或False。数组中的元素是由具有真值。

返回值 :

满足条件的数组元素。

# Python Program illustrating
# numpy.compress method
 
import numpy as geek
 
array = geek.arange(10).reshape(5, 2)
print("Original array : \n", array)
 
a = geek.mod(array, 4) !=0
# This will show element status of satisfying condition
print("\nArray Condition a : \n", a)
 
# This will return elements that satisfy condition "a" condition
print("\nElements that satisfy condition a  : \n", geek.extract(a, array))
 
 
 
b = array - 4 == 1
# This will show element status of satisfying condition
print("\nArray Condition b : \n", b)
 
# This will return elements that satisfy condition "b" condition
print("\nElements that satisfy condition b  : \n", geek.extract(b, array))

输出 :

Original array : 
 [[0 1]
 [2 3]
 [4 5]
 [6 7]
 [8 9]]

Array Condition a : 
 [[False  True]
 [ True  True]
 [False  True]
 [ True  True]
 [False  True]]

Elements that satisfy condition a  : 
 [1 2 3 5 6 7 9]

Array Condition b : 
 [[False False]
 [False False]
 [False  True]
 [False False]
 [False False]]

Elements that satisfy condition b  : 
 [5]