如何用numpy指令简化for循环遍历

Question

怎么用numpy指令来写图中的def啊，如何用numpy的形式，不用for和while循环等操作来达到图中def一样的功能？

Answer 1

import numpy as np

def c(x, y, z):
    x1 = x.reshape((len(x), 1))
    y1 = y.reshape((1, len(y)))
    a = x1 - y1
    q = np.where(a > 0, z, 0)
    q += np.where(a <= 0, z, 0)**2
    return q

x = np.arange(3)
print("x=:\n",x)

y = np.arange(4)
print("y=:\n", y)

z = np.arange(12).reshape(3, 4)
print("z=:\n", z)

q = c(x, y, z)
print("q=:\n", q)

x=:
 [0 1 2]
y=:
 [0 1 2 3]
z=:
 [[ 0  1  2  3]
 [ 4  5  6  7]
 [ 8  9 10 11]]
q=:
 [[  0   1   4   9]
 [  4  25  36  49]
 [  8   9 100 121]]