Numpy maskearray . dot()函数| Python
原文:https://www . geeksforgeeks . org/numpy-masked array-dot-function-python/
numpy.MaskedArray.dot() 函数用于计算两个掩膜阵列的点积。
语法:
numpy.ma.dot(arr1, arr2, strict=False)参数: arr1、arr 2:【ndarray】输入数组。 严格:【bool，可选】屏蔽数据是传播(True)还是设置为 0 (False)进行计算。默认值为假。
返回:【ndarray】arr 1 和 arr2 的点积。
代码#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)
Output:
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 --]]
代码#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)
Output:
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]]
