stripping away code in python using "re.sub"

Question

I read this: Stripping everything but alphanumeric chars from a string in Python

and this: Python: Strip everything but spaces and alphanumeric

Didn't quite understand but I tried a bit on my own code, which now looks like this:

import re

decrypt = str(open("crypt.txt"))

crypt = re.sub(r'([^\s\w]|_)+', '', decrypt)

print(crypt)

When I run the script It comes back with this answer: C:\Users\Adrian\Desktop\python>python tick.py ioTextIOWrapper namecrypttxt moder encodingcp1252

I am trying to get away all the extra code from the document and just keep numbers and letter, inside the document the following text can be found: http://pastebin.com/Hj3SjhxC

I am trying to solve the assignment here: http://www.pythonchallenge.com/pc/def/ocr.html

Anyone knows what "ioTextIOWrapper namecrypttxt moder encodingcp1252" means? And how should I format the code to properly strip it from everything except letter and numbers?

Sincerely

you should also tag this with `regex` – jackcogdill Jan 03 '13 at 21:58 — jackcogdill, Jan 03 '13 at 21:58

score 5 · Answer 1 · answered Jan 03 '13 at 22:00

str(open("file.txt")) doesn't do what you think it does. open() returns a file object. str gives you the string representation of that file object, not the contents of the file. If you want to read the contents of the file use open("file.txt").read().

Or, more safely, use a with statement:

with open("file.txt") as f:
    decrypt = f.read()
crypt = ... 
# etc.

score 3 · Accepted Answer · answered Jan 03 '13 at 22:00

3

You could just search for the alphanumeric chars instead. Like this:

print ''.join(re.findall('[A-Za-z]', decrypt))

And you also want:

decrypt = open("crypt.txt").read()

answered Jan 03 '13 at 22:00

jackcogdill

4,900
3
30
48

where is the "print ''.join(re.findall('[A-Za-z]', decrypt))" part going in my code? Thanks for fixing the open file problem I didnt even know I had :) – LoneDruidOfTheDarkArts Jan 03 '13 at 22:06
Well instead of removing everything except letters, it's much easier just to look for the letters themselves. – jackcogdill Jan 03 '13 at 22:10
[A-Z] means any letters from A to Z, and same with the a-z except lowercase – jackcogdill Jan 03 '13 at 22:10
Yea but I mean where should I put it? This is what I have done to the code now: import re decrypt = open("crypt.txt").read() print(''.join(re.findall('[A-Za-z]', decrypt) It results in the following error: C:\Users\Adrian\Desktop\python>python tick.py File "tick.py", line 12 ^ SyntaxError: unexpected EOF while parsing – LoneDruidOfTheDarkArts Jan 03 '13 at 22:14
1

Looks like you forgot a `)` at the end – jackcogdill Jan 03 '13 at 22:17
Yes! There it was! Thank you soooo much! :) – LoneDruidOfTheDarkArts Jan 03 '13 at 22:20
No Problem! :) Btw, if you ever need more help on regular expressions check out the Python docs [page](http://docs.python.org/2/library/re.html) on it – jackcogdill Jan 03 '13 at 22:31

stripping away code in python using "re.sub"

2 Answers2