Ruby Requires Chilkat v11.1.0+

Regular Expression with Multiple Matches and Named Capture Groups

See more Regular Expressions Examples

Demonstrates regular expressions with named capture groups and multiple matches. Ruby

require 'chilkat'

success = false

sb = Chilkat::CkStringBuilder.new()
crlf = true
sb.AppendLine("Name: John Smith",crlf)
sb.AppendLine("Name: Jack Johnson",crlf)
sb.AppendLine("Name: Mary Adams",crlf)

print sb.getAsString() + "\n";

#  We have the following string:
#  Name: John Smith
#  Name: Jack Johnson
#  Name: Mary Adams

pattern = "Name:\\s+(?<first>\\w+)\\s+(?<last>\\w+)"
json = Chilkat::CkJsonObject.new()
json.put_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() + "\n";
    exit
end

#  Examine the matches:
print json.emit() + "\n";

#  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": "Name: John Smith",
#            "idx": 0,
#            "len": 16
#          },
#          {
#            "cap": "John",
#            "idx": 6,
#            "len": 4
#          },
#          {
#            "cap": "Smith",
#            "idx": 11,
#            "len": 5
#          }
#        ]
#      },
#      {
#        "group": [
#          {
#            "cap": "Name: Jack Johnson",
#            "idx": 18,
#            "len": 18
#          },
#          {
#            "cap": "Jack",
#            "idx": 24,
#            "len": 4
#          },
#          {
#            "cap": "Johnson",
#            "idx": 29,
#            "len": 7
#          }
#        ]
#      },
#      {
#        "group": [
#          {
#            "cap": "Name: Mary Adams",
#            "idx": 38,
#            "len": 16
#          },
#          {
#            "cap": "Mary",
#            "idx": 44,
#            "len": 4
#          },
#          {
#            "cap": "Adams",
#            "idx": 49,
#            "len": 5
#          }
#        ]
#      }
#    ]
#  }

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

idx_first = json.IntOf("named.first")
idx_last = json.IntOf("named.last")

i = 0
matchCount = json.SizeOfArray("match")
while i < matchCount
    print "Match " + (i + 1).to_s() + ":" + "\n";
    json.put_I(i)

    json.put_J(idx_first)
    print "first: " + json.stringOf("match[i].group[j].cap") + "\n";

    json.put_J(idx_last)
    print "first: " + json.stringOf("match[i].group[j].cap") + "\n";

    print "" + "\n";
    i = i + 1
end

#  Output is: 

#  Match 1:
#  first: John
#  first: Smith
#  
#  Match 2:
#  first: Jack
#  first: Johnson
#  
#  Match 3:
#  first: Mary
#  first: Adams