CODEWITHSUNDEEP
pythonregex
Cryssie
Cryssie

Reputation: 3175

Retrieving log message within curly braces using Regex with Python

I am trying to parse some logs which return some responses in a key-pair format. I only want they value contained by the last key-pair (Rs: {".."}). The information I want are enclosed inside the curly braces.

What I have done is to use regex to match anything inside the curly braces like this:

import re

log = '2016-10-13 17:04:50 - info - uri:"GET x/y/z" ip:1.1.1.1 Rs:{"data": "blah blah"}'

text = re.compile("Rs\:{(.*)\}").search(log).group(1)
print (text)

>>> "data": "blah blah"

# Desired results
>>> {"data": "blah blah"}

However there are some issues doing it this way:

  1. I also wanted the starting curly braces and closing curly braces.

  2. This method doesn't work if there other opening ("{") or closing ("}:) curly braces before or inside the Rs values.

Is there a better way to do this?

Upvotes: 1

Views: 242

Answers (2)

cco
cco

Reputation: 6281

The first part is easy: just move the capturing parens out a little bit use this as your regex:

"Rs:(\{.*\})"

The other problem is more complicated - if you want the rest of the line (starting at {), then 

r'Rs:(\{.*)\Z'

would get you what you want.

Upvotes: 1

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626932

It seems that you need two things: re-adjust the first capturing group boundaries to include curly braces, and use a lazy version of .* (in case there are multiple values in the string). I also recommend checking if there is a match first if you are using re.search, or just use re.findall

import re
log = '2016-10-13 17:04:50 - info - uri:"GET x/y/z" ip:1.1.1.1 Rs:{"data": "blah blah"}'
text = re.compile(r"Rs:({[^}]*})").search(log)
if text:
    print (text.group(1))
# or
print(re.findall(r"Rs:({[^}]*})", log))

See the Python demo online

Pattern details:

Upvotes: 0

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