Regex to match key in YAML

Question

I have a yaml which looks like this..! User can define N number of xyz_flovor_id where _flovor_id key will be common. Aim is to grab *_flavor

Answer 1

You can use this regex:

\b[^_\n]+_flavor_id:\s*(\d+)

Click for Demo

Regex Explanation:

• \b - word boundary
• [^_\n]+ - 1+ occurrences of any character which is not an _ nor a newline character
• _flavor_id: - matches _flavor_id: literally
• \s* - matches 0+ occurences of a white space character
• (\d+) - matches and captures 1+ digits. This is the value that you needed.

I am not well versed with python but regex101 allows us to generate the code. So, I am pasting the code here which you can use.

import re

regex = r"\b[^_\n]+_flavor_id:\s*(\d+)"

test_str = ("server:\n"
    "    tenant: \"admin\"\n"
    "    availability_zone: \"nova\"\n"
    "    cpu_overcommit_ratio: 1:1\n"
    "    memory_overcommit_ratio: 1:1\n"
    "    xyz_flavor_id: 1\n"
    "    abc_flavor_id: 2")

matches = re.finditer(regex, test_str)

for matchNum, match in enumerate(matches):
    matchNum = matchNum + 1

    print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group()))

    for groupNum in range(0, len(match.groups())):
        groupNum = groupNum + 1

        print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum)))

This is the output I got: