小编Ser*_*nov的帖子

有没有办法让这个工作没有for循环？

import import numpy as np
import matplotlib.pyplot as plt    

L = 1
N = 255
dh = 2*L/N
dh2 = dh*dh

phi_0 = 1
c = int(N/2)
r_0 = L/2

arr = np.empty((N, N))

for i in range(N):

    for j in range(N):

            arr[i, j] = phi_0 if (i - c)**2 + (j - c)**2 < r_0**2/dh2 else 0


plt.imshow(arr)

我试过调用函数(x [None,:],y [:,None]),其中:

function(i, j):

    return phi_0 if (i - c)**2 + (j - c)**2 < r_0**2/dh2 else 0

但它需要list …