Ruby

Regular Expression with Multiple Matches and Capture Groups

See more Regular Expressions Examples

Demonstrates a regular expression with multiple matches and capture groups for each match.

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

Ruby

require 'chilkat'

success = false

pattern = "Name:\\s+(\\w+)\\s+(\\w+),\\s+Email:\\s+(\\S+)"

sb = Chilkat::CkStringBuilder.new()
crlf = true
sb.AppendLine("Name: John Smith, Email: john.smith@example.com",crlf)
sb.AppendLine("Name: Jack Johnson, Email: jack.johnson@example.com",crlf)
sb.AppendLine("Name: Mary Adams, Email: mary.adams@example.com",crlf)

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

# We have the following string:
# Name: John Smith, Email: john.smith@example.com
# Name: Jack Johnson, Email: jack.johnson@example.com
# Name: Mary Adams, Email: mary.adams@example.com

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";

# This is the JSON with the match information.
# See the JSON parsing code below to get the matched capture group values.

# {
#   "match": [
#     {
#       "group": [
#         {
#           "cap": "Name: John Smith, Email: john.smith@example.com",
#           "idx": 0,
#           "len": 47
#         },
#         {
#           "cap": "John",
#           "idx": 6,
#           "len": 4
#         },
#         {
#           "cap": "Smith",
#           "idx": 11,
#           "len": 5
#         },
#         {
#           "cap": "john.smith@example.com",
#           "idx": 25,
#           "len": 22
#         }
#       ]
#     },
#     {
#       "group": [
#         {
#           "cap": "Name: Jack Johnson, Email: jack.johnson@example.com",
#           "idx": 49,
#           "len": 51
#         },
#         {
#           "cap": "Jack",
#           "idx": 55,
#           "len": 4
#         },
#         {
#           "cap": "Johnson",
#           "idx": 60,
#           "len": 7
#         },
#         {
#           "cap": "jack.johnson@example.com",
#           "idx": 76,
#           "len": 24
#         }
#       ]
#     },
#     {
#       "group": [
#         {
#           "cap": "Name: Mary Adams, Email: mary.adams@example.com",
#           "idx": 102,
#           "len": 47
#         },
#         {
#           "cap": "Mary",
#           "idx": 108,
#           "len": 4
#         },
#         {
#           "cap": "Adams",
#           "idx": 113,
#           "len": 5
#         },
#         {
#           "cap": "mary.adams@example.com",
#           "idx": 127,
#           "len": 22
#         }
#       ]
#     }
#   ]
# }

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

i = 0
matchCount = json.SizeOfArray("match")
while i < matchCount
    print "Match " + (i + 1).to_s() + ":" + "\n";
    json.put_I(i)
    j = 0
    numCaptureGroups = json.SizeOfArray("match[i].group")
    while j < numCaptureGroups
        json.put_J(j)
        cap = json.stringOf("match[i].group[j].cap")
        print j.to_s() + ": " + cap + "\n";
        j = j + 1
    end
    i = i + 1
end

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

# Output

# Match 1:
# 0: Name: John Smith, Email: john.smith@example.com
# 1: John
# 2: Smith
# 3: john.smith@example.com
# Match 2:
# 0: Name: Jack Johnson, Email: jack.johnson@example.com
# 1: Jack
# 2: Johnson
# 3: jack.johnson@example.com
# Match 3:
# 0: Name: Mary Adams, Email: mary.adams@example.com
# 1: Mary
# 2: Adams
# 3: mary.adams@example.co