How can I tell when a string is in fact a number?

[Joshua Muskovitz]

> Here's another whimsical solution (to the digits-only problem),
> with _peculiar_ failings...
>
> def isanum(str):
>     l=list(str)
>     l.sort()
>     return l[0]>='0' and l[-1]<='9'
>
> Apart from little defects such as being O(N log N), and breaking
> for the empty-string, I wonder if there's any Python implementation
> where this will really fall apart (EBCDIC...?).

I believe that even in EBCDIC, digits form a contiguous part of the encoding
space.  And thanks for pointing out that the question and the reference
implementation were inconsistent.  I think I've had too many years of this
sort of work -- I only look at the reference implementation!  :-)

-- josh





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