python中字典的复制

 

1、

>>> a = dict(zip(("a","b","c","d"),(111,222,333,444)))
>>> a
{'a': 111, 'b': 222, 'c': 333, 'd': 444}
>>> b = a          ## 假复制
>>> b
{'a': 111, 'b': 222, 'c': 333, 'd': 444}
>>> a["a"] = "xxxx"
>>> a
{'a': 'xxxx', 'b': 222, 'c': 333, 'd': 444}
>>> b
{'a': 'xxxx', 'b': 222, 'c': 333, 'd': 444}

 

2、

>>> a = dict(a = 111, b = 222, c = 333, d = 444)
>>> a
{'a': 111, 'b': 222, 'c': 333, 'd': 444}
>>> b = a.copy()      ## 真复制
>>> b
{'a': 111, 'b': 222, 'c': 333, 'd': 444}
>>> a["a"] = "xxxx"
>>> a
{'a': 'xxxx', 'b': 222, 'c': 333, 'd': 444}
>>> b
{'a': 111, 'b': 222, 'c': 333, 'd': 444}