python将数组写入文件

import numpy as np
data = np.array([[1,2],
 [3,4]])

#np.savetxt('out.txt', data)
#np.savetxt('out.txt', data, fmt="%d") #保存为整数
np.savetxt('out.txt', data, fmt="%.2f", delimiter=',') #保存为2位小数的浮点数，用逗号分隔
with open('out.txt') as f:
 for line in f:
 print(line, end='')