regex/lambda black magic

[Andrew Robert]

Hi everyone,

I have two test scripts, an encoder and a decoder.

The encoder, listed below, works perfectly.


import re,sys
output = open(r'e:\pycode\out_test.txt','wb')
for line in open(r'e:\pycode\sigh.txt','rb') :
    output.write( re.sub(r'([^\w\s])', lambda s: '%%%2X' %
ord(s.group()), line))


The decoder, well, I have hopes.


import re,sys
output = open(r'e:\pycode\new_test.txt','wb')
for line in open(r'e:\pycode\out_test.txt','rb') :
   output.write( re.sub(r'([^\w\s])', lambda s: chr(int(s.group(), 16))
% ord(s.group()), line))


The decoder generates the following traceback:

Traceback (most recent call last):
  File "E:\pycode\sample_decode_file_specials_from_hex.py", line 9, in ?
    output.write( re.sub(r'([^\w\s])', lambda s: chr(int(s.group(), 16))
% ord(s.group()), line))
  File "C:\Python24\lib\sre.py", line 142, in sub
    return _compile(pattern, 0).sub(repl, string, count)
  File "E:\pycode\sample_decode_file_specials_from_hex.py", line 9, in
<lambda>
    output.write( re.sub(r'([^\w\s])', lambda s: chr(int(s.group(), 16))
% ord(s.group()), line))
ValueError: invalid literal for int(): %

Does anyone see what I am doing wrong?