trying to match a string

oj ojeeves at
Fri Jul 18 13:05:47 CEST 2008

On Jul 18, 11:33 am, arnimavidyar... at wrote:
> Hi,
> Hi,
> I am taking a string as an input from the user and it should only
> contain the chars:L , M or R
> I tried the folllowing in kodos but they are still not perfect:
> [^A-K,^N-Q,^S-Z,^0-9]
> [L][M][R]
> [LRM]?L?[LRM]? etc but they do not exactly meet what I need.
> For eg: LRLRLRLRLM is ok but LRLRLRNL is not as it has 'N' .like that.
> regards,
> SZ
> The string may or may not have all the three chars.

With regular expressions, [^LRM] matches a character that isn't L, R
or M. So:

import re


if'[^LRM]', var):
    print "Invalid"

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