Visual FoxPro

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

Visual FoxPro

LOCAL lnSuccess
LOCAL lcPattern
LOCAL loSb
LOCAL lnCrlf
LOCAL loJson
LOCAL lnTimeoutMs
LOCAL lnNumMatches
LOCAL lcCap
LOCAL i
LOCAL lnMatchCount
LOCAL j
LOCAL lnNumCaptureGroups

lnSuccess = 0

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

loSb = CreateObject('Chilkat.StringBuilder')
lnCrlf = 1
loSb.AppendLine("Name: John Smith, Email: john.smith@example.com",lnCrlf)
loSb.AppendLine("Name: Jack Johnson, Email: jack.johnson@example.com",lnCrlf)
loSb.AppendLine("Name: Mary Adams, Email: mary.adams@example.com",lnCrlf)

? loSb.GetAsString()

* 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

loJson = CreateObject('Chilkat.JsonObject')
loJson.EmitCompact = 0

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
    CANCEL
ENDIF

* Examine the matches:
? loJson.Emit()

* 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
lnMatchCount = loJson.SizeOfArray("match")
DO WHILE i < lnMatchCount
    ? "Match " + STR(i + 1) + ":"
    loJson.I = i
    j = 0
    lnNumCaptureGroups = loJson.SizeOfArray("match[i].group")
    DO WHILE j < lnNumCaptureGroups
        loJson.J = j
        lcCap = loJson.StringOf("match[i].group[j].cap")
        ? STR(j) + ": " + lcCap
        j = j + 1
    ENDDO
    i = i + 1
ENDDO

* 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

RELEASE loSb
RELEASE loJson