CODEWITHSUNDEEP
pythonregex
Shraddha
Shraddha

Reputation: 2579

Matching multiple groups in string

I have a string like 'testname=ns,mem=2G'

After parsing the above string I want to assign a variable tstnm to ns and variable memory to 2G

import re
str = "testname=ns,mem=2G"

b = re.search('(?<=testname=)\w+', str)
m = re.search('(?<=mem=)\w+', str)
if b:
     tstnm = b.group(0)
if m:
     memory = m.group(0)

which works , but then when I tried to do it in one go , like -

m = re.search('(?<=testname=)(\w+)\,(?<=mem=)(\w+)', str)

m is None //

Upvotes: 3

Views: 86

Answers (3)

thefourtheye
thefourtheye

Reputation: 239443

Should you be using regex for this? How about simple string operations

inputString = "testname=ns,mem=2G"
result = inputString.split(",")
tstnm  = result[0].split("=")[1]
memory = result[1].split("=")[1]
print tstnm, memory

Output

ns 2G

Upvotes: 1

stema
stema

Reputation: 92976

That is because you are using lookaround assertions. They do only match a position, but not the string inside the groups. So, with \,(?<=mem=)(\w+) you are creating a regex that can never be true, because \,(?<=mem=) is always false.

You could use capturing groups instead:

import re
input = "testname=ns,mem=2G"

result = re.search('testname=(\w+),mem=(\w+)', input)
if result:
     tstnm = result.group(1)
     memory = result.group(2)

Upvotes: 3

Rohit Jain
Rohit Jain

Reputation: 213213

Use re.findall(), and you can merge your regex using pipe(|):

>>> s = "testname=ns,mem=2G"
>>> re.findall('(?<=testname=)\w+|(?<=mem=)\w+', s)
['ns', '2G']

Don't use str as variable name.

Upvotes: 4

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