Python中的 numpy.extract()

如果它们满足某些指定条件， numpy.extract()函数将返回 input_array 的元素。

Syntax: numpy.extract(condition, array)

参数 ：

array     : Input array. User apply conditions on input_array elements
condition : [array_like]Condition on the basis of which user extract elements. 
      Applying condition on input_array, if we print condition, it will return an array
      filled with either True or False. Array elements are extracted from the Indices having 
      True value.

返回：

Array elements that satisfy the condition.

Python

# 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]