(Chilkat2-Python) Regular Expression with Named Capture Groups

See more Regular Expressions Examples

See the sample code below.

Note: Chilkat uses PCRE2. See PCRE2 Regular Expressions
Also see: PCRE2 Performance

In PCRE2, named capture groups allow you to assign a name to a capturing group, making it easier to reference by name instead of number.

Syntax

(?<name>pattern)

or

(?'name'pattern)

Example

(?<first>\w+)\s+(?<last>\w+)

Applied to:

"John Smith"

Produces:

• first: John
• last: Smith

Note: This example requires Chilkat v11.1.0 or greater.

Chilkat2 Python Downloads install with pip pip3 install chilkat2 or download... Python Module for Windows, Linux, Alpine Linux, MacOS

import sys
import chilkat2

success = False

subject = "John Smith"
pattern = "(?<first>\\w+)\\s+(?<last>\\w+)"

sb = chilkat2.StringBuilder()
sb.Append(subject)

json = chilkat2.JsonObject()
json.EmitCompact = False

timeoutMs = 2000
numMatches = sb.RegexMatch(pattern,json,timeoutMs)
if (numMatches < 0):
    # Probably an error in the regular expression.
    # Suggestion: Use AI to help create and/or diagnose regular expressions.
    print(sb.LastErrorText)
    sys.exit()

# Examine the matches:
print(json.Emit())

# Here is the JSON showing the matches.
# Important:  Capture group 0 always contains the entire match — that is, the portion of the input string that matches the full regular expression.

# {
#   "named": {
#     "first": 1,
#     "last": 2
#   },
#   "match": [
#     {
#       "group": [
#         {
#           "cap": "John Smith",
#           "idx": 0,
#           "len": 10
#         },
#         {
#           "cap": "John",
#           "idx": 0,
#           "len": 4
#         },
#         {
#           "cap": "Smith",
#           "idx": 5,
#           "len": 5
#         }
#       ]
#     }
#   ]
# }

# The capture group index is obtained by looking up the name in the JSON result.
# For example:

json.I = json.IntOf("named.first")
print("first: " + json.StringOf("match[0].group[i].cap"))

json.I = json.IntOf("named.last")
print("last: " + json.StringOf("match[0].group[i].cap"))

# Output is: 

# first: John
# last: Smith