大哥，小弟想请教一个 Python 问题

需求，把三个列表 a,b,c,转换为嵌套一个列表 x 打印 x，结果为[['A', 'AA', 'AAA'], ['B', 'BB', 'BBB'], ['C', 'CC', 'CCC']]

代码如下，当前代码符合需求，运行正常

如果把疑惑的部分 x 赋值代码替换为注释部分的代码，执行结果便不是所期望的那样.替换后，执行结果是
[ ['C', 'CC', 'CCC'], ['C', 'CC', 'CCC'], ['C', 'CC', 'CCC']]
为什么会这样啊

# Create your tests here.
a = ['A', 'B', 'C']
b = ['AA', 'BB', 'CC']
c = ['AAA', 'BBB', 'CCC']

#有疑惑部分
x = [["0"] * 3 for i in range(3)]
"""
item = ["0", "0", "0"]
x = []
for i in range(3):
    x.append(item)
"""

j = 0
for i in a:
    x[j][0] = i
    j = j + 1

j = 0
for i in b:
    x[j][1] = i
    j = j + 1

j = 0
for i in c:
    x[j][2] = i
    j = j + 1

print x