Pythonic way to determine if a string is a number

[python at bdurham.com]

Thanks for everyone's feedback. I believe my original post's code
(updated following my signature) was in line with this list's feedback.

Christian: Thanks for reminding me about exponential formats. My updated
code accounts for these type of numbers. I don't need to handle inf or
nan values. My original code's except catches an explicit ValueError
exception per your concern about bare excepts.

Malcolm

<code>
# str_to_num.py

def isnumber( input ):
    try:
        num = float( input )
        return True

    except ValueError:
        return False

if __name__ == '__main__':
    tests = """
        12
        -12
        -12.34
        .0
        .
        1 2 3
        1 . 2

        1e10
        1E10
        inf
        nan

        12 and text
        just text
    """

    for test in tests.split( '\n' ):
        print 'test (%0s), isnumber: %1s' % ( test.strip(), isnumber(
        test ) )
</code>