#coding:utf-8import randomclass SymMat(object): def __init__(self, length=4): self.length = length self.matrix = [[0]*length]*length values = range(length*2) v = random.sample(values, length) pprint(self.matrix) print '------------before' self.matrix[1][0:] = v pprint(self.matrix)def pprint(l): for i in l: print ism = SymMat(5)
输出:
[0, 0, 0, 0, 0][0, 0, 0, 0, 0][0, 0, 0, 0, 0][0, 0, 0, 0, 0][0, 0, 0, 0, 0]------------before[7, 9, 4, 3, 5][7, 9, 4, 3, 5][7, 9, 4, 3, 5][7, 9, 4, 3, 5][7, 9, 4, 3, 5]
仅对列表中第一行赋值,应该仅仅改变一行的,百思不解!问题已解决,* 赋值的时候是直接引用过去的,n个列表id相等~~
解决方案
这种问题好多人都遇到,懒得再说一遍了,看链接: https://groups.google.com/d/msg/python-cn/CDV1D7vdq6E/0EO9kjVU4dcJ