Python numpy.place()用法及代码示例

numpy.place(array，mask，vals)：根据参数-条件和值在数组中进行更改(根据用户设置的掩码，使用第一个N-values放入数组中)。它与numpy.extract()相反。

参数：

array : [ndarray] Input array, we need to make changes into
mask  : [array_like]Boolean that must have same size as that of the input array
value : Values to put into the array. Based on the mask condition it adds only N-elements
    to the array. If in case values in val are smaller than the mask, same values get repeated.

返回：

Array with change elements i.e. new elements being put

# Python Program illustrating 
# numpy.place() method 
   
import numpy as geek 
   
array = geek.arange(12).reshape(3, 4) 
print("Original array : \n", array) 
   
# Putting new elements 
a = geek.place(array, array > 5, [15, 25, 35]) 
print("\nPutting up elements to array: \n", array) 
  
  
array1 = geek.arange(6).reshape(2, 3) 
print("\n\nOriginal array1 : \n", array) 
  
# Putting new elements 
a = geek.place(array1, array1>2, [44, 55]) 
print("\nPutting new elements to array1 : \n", array1)

输出：

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

Putting up elements to array: 
 [[ 0  1  2  3]
 [ 4  5 15 25]
 [35 15 25 35]]


Original array1 : 
 [[ 0  1  2  3]
 [ 4  5 15 25]
 [35 15 25 35]]

Putting new elements to array1 : 
 [[ 0  1  2]
 [44 55 44]]

参考文献：
https://docs.scipy.org/doc/numpy-dev/reference/generated/numpy.place.html#numpy.place