python: How to determine if a string contains a tuple?

I need a clean way to determine if a string is actually a tuple, like so:

'(123,456)' --> True

'hello world' --> False

I can think of two ways to do this:

开发者_开发问答

1. a regex
2. call eval and catch/ignore a SyntaxError

I don't like the second option. I'm fine with the first option but just wanted to know if there was a better way to do it.

Thanks.

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def represents_tuple(s):
    try: return type(ast.literal_eval(s)) == tuple
    except SyntaxError: return False
    except ValueError: return False

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If the tuple inside the string can only have simple numbers, then use a regex. If the tuple members can be arbitrarily complex (such as nested lists), use eval.