Python Numpy MaskedArray.dot()用法及代碼示例

numpy.MaskedArray.dot()函數用於計算兩個蒙版陣列的點積。

用法： numpy.ma.dot(arr1, arr2, strict=False)

參數：
arr1，arr2：[ndarray]輸入數組。
strict :[布爾，可選]是傳播掩碼數據(真)還是將其設置為0(假)以進行計算。默認值為False。

Return :[ndarray] arr1和arr2的點積。

代碼1：

# Python program explaining 
# numpy.MaskedArray.dot() method  
    
# importing numpy as geek   
# and numpy.ma module as ma  
import numpy as geek  
import numpy.ma as ma  
    
# creating input arrays    
in_arr1 = geek.array([[1, 2], [ 3, 4]]) 
print ("1st Input array:", in_arr1)  
    
in_arr2 = geek.array([[-1, -2], [ -3, -4]])  
print ("2nd Input array:", in_arr2)  
    
      
# Now we are creating  masked array.   
# by making  entry as invalid    
mask_arr1 = ma.masked_array(in_arr1, mask = [[ 1, 0], [ 0, 1]])   
print ("1st Masked array:", mask_arr1)  
    
mask_arr2 = ma.masked_array(in_arr2, mask =[[ 0, 1], [ 0, 0]])   
print ("2nd Masked array:", mask_arr2)  
    
# applying MaskedArray.dot methods   
# to masked array   
out_arr = ma.dot(mask_arr1, mask_arr2)   
print ("Dot product of two arrays:", out_arr)

輸出：

1st Input array: [[1 2]
 [3 4]]
2nd Input array: [[-1 -2]
 [-3 -4]]
1st Masked array: [[-- 2]
 [3 --]]
2nd Masked array: [[-1 --]
 [-3 -4]]
Dot product of two arrays: [[-6 -8]
 [-3 --]]

代碼2：

# Python program explaining 
# numpy.MaskedArray.dot() method  
    
# importing numpy as geek   
# and numpy.ma module as ma  
import numpy as geek  
import numpy.ma as ma  
    
# creating input arrays    
in_arr1 = geek.array([[1, 2], [ 3, -1], [ 5, -3]]) 
print ("1st Input array:", in_arr1)  
    
in_arr2 = geek.array([[1, 0, 3], [ 4, 1, 6]])  
print ("2nd Input array:", in_arr2)  
    
      
# Now we are creating  masked array.   
# by making  entry as invalid    
mask_arr1 = ma.masked_array(in_arr1, mask = [[ 1, 0], [ 0, 1], [ 0, 0]])   
print ("1st Masked array:", mask_arr1)  
    
mask_arr2 = ma.masked_array(in_arr2, mask =[[ 0, 0, 0], [ 0, 0, 1]])   
print ("2nd Masked array:", mask_arr2)  
    
# applying MaskedArray.dot methods   
# to masked array   
out_arr = ma.dot(mask_arr1, mask_arr2)   
print ("Dot product of two arrays:", out_arr)

輸出：

1st Input array: [[ 1  2]
 [ 3 -1]
 [ 5 -3]]
2nd Input array: [[1 0 3]
 [4 1 6]]
1st Masked array: [[-- 2]
 [3 --]
 [5 -3]]
2nd Masked array: [[1 0 3]
 [4 1 --]]
Dot product of two arrays: [[8 2 --]
 [3 0 9]
 [-7 -3 15]]

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注：本文由純淨天空篩選整理自jana_sayantan大神的英文原創作品 Numpy MaskedArray.dot() function | Python。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。