Numpy maskearray . average()函数| Python
原文:https://www . geeksforgeeks . org/numpy-masked array-average-function-python/
numpy.MaskedArray.average() 函数用于返回给定轴上数组的加权平均值。
语法:
numpy.ma.average(arr, axis=None, weights=None, returned=False)参数:
arr:【array _ like】输入要平均其数据的屏蔽数组。计算中不考虑屏蔽条目。 轴:【整数，可选】平均 arr 所沿的轴。如果“无”，则对展平的数组进行平均。 权重:【array _ like，可选】每个元素在平均值计算中的重要性。如果权重=无，则假定 arr 中的所有数据的权重都等于 1。如果权重很复杂，虚部将被忽略。 返回:【bool，可选】表示元组(结果，权重之和)是作为输出返回(True)，还是只返回结果(False)。默认值为假。
返回:【标量或掩码数组】沿指定轴的平均值。当返回为真时，返回一个元组，平均值作为第一个元素，权重之和作为第二个元素。
代码#1 :
# Python program explaining
# numpy.MaskedArray.average() method
# importing numpy as geek
# and numpy.ma module as ma
import numpy as geek
import numpy.ma as ma
# creating input array
in_arr = geek.array([[1, 2], [ 3, -1], [ 5, -3]])
print ("Input array : ", in_arr)
# Now we are creating a masked array.
# by making entry as invalid.
mask_arr = ma.masked_array(in_arr, mask =[[1, 0], [ 1, 0], [ 0, 0]])
print ("Masked array : ", mask_arr)
# applying MaskedArray.average
# methods to masked array
out_arr = ma.average(mask_arr)
print ("normal average of masked array : ", out_arr)
Output:
Input array : [[ 1 2]
[ 3 -1]
[ 5 -3]]
Masked array : [[-- 2]
[-- -1]
[5 -3]]
normal average of masked array : 0.75
代码#2 :
# Python program explaining
# numpy.MaskedArray.average() method
# importing numpy as geek
# and numpy.ma module as ma
import numpy as geek
import numpy.ma as ma
# creating input array
in_arr = geek.array([[1, 2], [ 3, -1], [ 5, -3]])
print ("Input array : ", in_arr)
# Now we are creating a masked array.
# by making entry as invalid.
mask_arr = ma.masked_array(in_arr, mask =[[1, 0], [ 1, 0], [ 0, 0]])
print ("Masked array : ", mask_arr)
# applying MaskedArray.average
# methods to masked array
out_arr = ma.average(mask_arr, weights =[[0, 1], [ 0, 2], [ 3, 1]])
print ("weighted average of masked array : ", out_arr)
Output:
Input array : [[ 1 2]
[ 3 -1]
[ 5 -3]]
Masked array : [[-- 2]
[-- -1]
[5 -3]]
weighted average of masked array : 1.7142857142857142
