import re s='abcdatraataza' r=re.compile('(?<!a)a(?!a)') a_list=[ match.start() for match in re2.finditer(s) ]
Oops, tested this time: ----------------------------
import re
def index_letters(s,l): regexp='(?<!%s)%s(?!%s)' % (l,l,l) r=re.compile(regexp) return [ match.start() for match in r.finditer(s) ]
print index_letters('abcdatraataza','a')
-- Pádraig Brady - http://www.pixelbeat.org -- -- http://mail.python.org/mailman/listinfo/python-list
