regex question

[proctor]

hello,

i hope this is the correct place...

i have an issue with some regex code i wonder if you have any insight:

================

import re, sys

def makeRE(w):
	print w + " length = " + str(len(w))
	reString = "r'" + w[:1]
	w = w[1:]
	if len(w) > 0:
		for c in (w):
			reString += "|" + c
	reString += "'"
	print "reString = " + reString
	return reString

test = sys.argv[1]
stg = sys.argv[2]

while test:
	print "test = ", test
	print "stg = ", stg
	rx_a = re.compile(makeRE(test))
	i = rx_a.search(stg).start()
	print "i = " + str(i)
	id = test.find(stg[i])
	test = test[:id] + test[id+1:]
	print "test == ", test
	stg = stg[:i] + stg[i+1:]
	print

================

i get the following output:

================

test =  abc
stg =  defabc
abc length = 3
reString = r'a|b|c'
i = 4
test ==  ac

test =  ac
stg =  defac
ac length = 2
reString = r'a|c'
Traceback (most recent call last):
  File "aaaa.py", line 21, in ?
    i = rx_a.search(stg).start()
AttributeError: 'NoneType' object has no attribute 'start'

=================

i am fairly new to this, and can't see the reason for the error.  what
am i missing?

btw, i think there are simpler ways to go about this, but i am doing it
this way (regexs) for a bit of a challenge and learning experience.

thanks to all!

sincerely,
proctor