RegEx: find all occurances of a single character in a string
P at draigBrady.com
P at draigBrady.com
Tue Dec 14 12:15:03 EST 2004
Franz Steinhaeusler wrote:
> given a string:
>
> st="abcdatraataza"
> ^ ^ ^ ^ (these should be found)
> I want to get the positions of all single 'a' characters.
> (Without another 'a' neighbour)
>
> So I tried:
> r=re.compile('[^a]a([^a]')
>
> but this applies only for
> the a's, which has neighbours.
> So I need also '^a' and 'a$'.
>
> Am I doing something wrong?
> Is there a easier solution?
> How can I quickly get all these positions?
>
> Thank you in advance.
import re
s='abcdatraataza'
r=re.compile('(?<!a)a(?!a)')
a_list=[ match.start() for match in re2.finditer(s) ]
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Pádraig Brady - http://www.pixelbeat.org
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