按行比较数组以推广 argmax 函数

Question

使用Python，考虑包含二维数据的数组X：

X = np.array([x0,y0], ..., [xn,yn])

和三个一维数组 Y_A, Y_B, Y_C，长度与 X 相同，包含数字。最后考虑 3 个空数组 A,B,C。如何根据以下伪代码填充这些空数组A,B,C？

伪代码:

for each i in range(X):
   if Y_A[i] > Y_B[i] and Y_A[i] > Y_C[i]
   store X[i] to array A
   else if Y_B[i] > Y_A[i] and Y_B[i] > Y_C[i]
   store X[i] to array B
   else store X[i] to array C

我的努力无效:

for each i in range(len(X)):
    if Y_A[i] > Y_B[i] and Y_A[i] > Y_C[i]:
        A = Y_A
    if Y_B[i] > Y_A[i] and Y_B[i] > Y_C[i]:
        B = Y_B
    else:
        C = Y_C

Answer 1

也许可以试试这样：

import numpy as np

X = np.random.random((20, 2))
Y_A = np.random.random((20))
Y_B = np.random.random((20))
Y_C = np.random.random((20))

A, B, C = [], [], [] 
for i in range(X.shape[0]):
   if Y_A[i] > Y_B[i] and Y_A[i] > Y_C[i]:
     A.append(X[i])
   elif Y_B[i] > Y_A[i] and Y_B[i] > Y_C[i]:
     B.append(X[i])
   else:
     C.append(X[i])

A = np.array(A)
B = np.array(B)
C = np.array(C)

当然，如果它们的长度与 X 相同，您也可以创建空的 numpy 数组并在循环时填充它们。

按行比较数组以推广 argmax 函数

Comparing array row-wise so as to generalize argmax function

python

numpy

pseudocode

argmax