trying to match a string

Eddie Corns eddie at holyrood.ed.ac.uk
Fri Jul 18 12:46:53 CEST 2008


arnimavidyarthy at gmail.com writes:

>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.


>>> var     = 'LRLRLRNL'
>>> residue = var.replace('L','').replace('R','').replace('M','')
>>> if residue != '':
...   print 'Invalid characters in input',residue
... 
Invalid characters in input N



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