Lianja

Regular Expression with Multiple Matches and Named Capture Groups

See more Regular Expressions Examples

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

llSuccess = .F.

loSb = createobject("CkStringBuilder")
llCrlf = .T.
loSb.AppendLine("Name: John Smith",llCrlf)
loSb.AppendLine("Name: Jack Johnson",llCrlf)
loSb.AppendLine("Name: Mary Adams",llCrlf)

? loSb.GetAsString()

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

lcPattern = "Name:\\s+(?<first>\\w+)\\s+(?<last>\\w+)"
loJson = createobject("CkJsonObject")
loJson.EmitCompact = .F.

lnTimeoutMs = 2000
lnNumMatches = loSb.RegexMatch(lcPattern,loJson,lnTimeoutMs)
if (lnNumMatches < 0) then
    // Probably an error in the regular expression.
    // Suggestion: Use AI to help create and/or diagnose regular expressions.
    ? loSb.LastErrorText
    release loSb
    release loJson
    return
endif

// Examine the matches:
? loJson.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": "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:

lnIdx_first = loJson.IntOf("named.first")
lnIdx_last = loJson.IntOf("named.last")

i = 0
lnMatchCount = loJson.SizeOfArray("match")
do while i < lnMatchCount
    ? "Match " + str(i + 1) + ":"
    loJson.I = i

    loJson.J = lnIdx_first
    ? "first: " + loJson.StringOf("match[i].group[j].cap")

    loJson.J = lnIdx_last
    ? "first: " + loJson.StringOf("match[i].group[j].cap")

    ? ""
    i = i + 1
enddo

// Output is: 

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


release loSb
release loJson