将集合转换为字符串，反之亦然
问题描述
设置为字符串.很明显:
Set to string. Obvious:
>>> s = set([1,2,3])
>>> s
set([1, 2, 3])
>>> str(s)
'set([1, 2, 3])'
要设置的字符串?也许是这样?
String to set? Maybe like this?
>>> set(map(int,str(s).split('set([')[-1].split('])')[0].split(',')))
set([1, 2, 3])
非常丑陋.有没有更好的方法来序列化/反序列化集合?
Extremely ugly. Is there better way to serialize/deserialize sets?
解决方案
使用 repr 和 eval:
>>> s = set([1,2,3])
>>> strs = repr(s)
>>> strs
'set([1, 2, 3])'
>>> eval(strs)
set([1, 2, 3])
请注意，如果字符串的来源未知，eval 是不安全的，为了更安全的转换，首选 ast.literal_eval:
Note that eval is not safe if the source of string is unknown, prefer ast.literal_eval for safer conversion:
>>> from ast import literal_eval
>>> s = set([10, 20, 30])
>>> lis = str(list(s))
>>> set(literal_eval(lis))
set([10, 20, 30])
repr 的帮助:
repr(object) -> string
Return the canonical string representation of the object.
For most object types, eval(repr(object)) == object.
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