using split for a string : error
Steven D'Aprano
steve+comp.lang.python at pearwood.info
Thu Jan 24 19:20:42 EST 2013
Chris Angelico wrote:
> It's usually fine to have int() complain about any non-numerics in the
> string, but I must confess, I do sometimes yearn for atoi() semantics:
> atoi("123asd") == 123, and atoi("qqq") == 0. I've not seen a
> convenient Python function for doing that. Usually it involves
> manually getting the digits off the front. All I want is to suppress
> the error on finding a non-digit. Oh well.
It's easy enough to write your own. All you need do is decide what you
mean by "suppress the error on finding a non-digit".
Should atoi("123xyz456") return 123 or 123456?
Should atoi("xyz123") return 0 or 123?
And here's a good one:
Should atoi("1OOl") return 1, 100, or 1001?
That last is a serious suggestion by the way. There are still many people
who do not distinguish between 1 and l or 0 and O.
Actually I lied. It's not that easy. Consider:
py> s = '໑໒໙'
py> int(s)
129
Actually I lied again. It's not that hard:
def atoi(s):
from unicodedata import digit
i = 0
for c in s:
i *= 10
i += digit(c, 0)
return i
Variations that stop on the first non-digit, instead of treating them as
zero, are not much more difficult.
--
Steven
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