Regex End Of Line And Specific Chracters

So I'm writing a Python program that reads lines of serial data, and compares them to a dictionary of line codes to figure out which specific lines are being transmitted. I am att

Solution 1:

Your problem is threefold:

1) your string contains extra \r (Carriage Return character) before \n (New Line character); this is common in Windows and in network communication protocols; it is probably best to remove any trailing whitespace from your string:

regexString = regexString.rstrip()

2) as mentioned by Wiktor Stribiżew, your regexp is unnecessarily surrounded with / characters - some languages, like Perl, define regexp as a string delimited by / characters, but Python is not one of them;

3) your instruction using re.sub is actually replacing the matching part of regexString with an empty string - I believe this is the exact opposite of what you want (you want to keep the match and remove everything else, right?); that's why fixing the regexp makes things "even worse".

To summarize, I think you should use this instead of your current code:

m = re.match('T12F8B0A22[A-Z0-9]{2}F8', regexString)
regexString = m.group(0)

Solution 2:

There are several ways to get rid of the "\r", but first a little analysis of your code : 1. the special charakter for the end is just '$' not '$\' in python. 2. re.sub will substitute the matched pattern with a string ( '' in your case) wich would substitute the string you want to get with an empty string and you are left with the //r

possible solutions:

1. use simple replace:

    regexString.replace('\\r','')
   

2. if you want to stick to regex the approach is the same

   pattern = '\\\\r'         
   match = re.sub(pattern, '',regexString)
   

2.2 if you want the acces the different groubs use re.search

    match = re.search('(^T12F8B0A22[A-Z0-9]{2}F8)(.*)',regexString)
    match.group(1) # will give you the T12...
    match.groupe(2) # gives you the \\r

Solution 3:

Just match what you want to find. Couple of examples:

import re

data = '''lots of
otherT12F8B0A2212F8garbage
T12F8B0A2234F8around
T12F8B0A22ABF8the
stringsT12F8B0A22CDF8
'''

print(re.findall('T12F8B0A22..F8',data))

['T12F8B0A2212F8', 'T12F8B0A2234F8', 'T12F8B0A22ABF8', 'T12F8B0A22CDF8']

m = re.search('T12F8B0A22..F8',data)
if m:
    print(m.group(0))

T12F8B0A2212F8