VB.NET

Regular Expression Replace Full Matches

See more Regular Expressions Examples

Demonstrates replacing the full matches of a regular expression.

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

VB.NET

Dim success As Boolean = False

success = False

Dim subject As String = "John Anders, +_+_+ Mary Robins $$$$"
Dim pattern As String = "\w+\s+\w+"

Dim sb As New Chilkat.StringBuilder
sb.Append(subject)

Dim json As New Chilkat.JsonObject
json.EmitCompact = False

Dim timeoutMs As Integer = 2000
Dim numMatches As Integer = sb.RegexMatch(pattern,json,timeoutMs)
If (numMatches < 0) Then
    ' Probably an error in the regular expression.
    ' Suggestion: Use AI to help create and/or diagnose regular expressions.
    Debug.WriteLine(sb.LastErrorText)
    Exit Sub
End If


' Examine the matches:
Debug.WriteLine(json.Emit())

' {
'   "match": [
'     {
'       "group": [
'         {
'           "cap": "John Anders",
'           "idx": 0,
'           "len": 11
'         }
'       ]
'     },
'     {
'       "group": [
'         {
'           "cap": "Mary Robins",
'           "idx": 19,
'           "len": 11
'         }
'       ]
'     }
'   ]
' }

Dim sbTemp As New Chilkat.StringBuilder

Dim i As Integer = 0
numMatches = json.SizeOfArray("match")
While i < numMatches

    json.I = i

    ' The full match is always in group 0.
    sbTemp.Clear()
    json.StringOfSb("match[i].group[0].cap",sbTemp)

    ' Indicate that we wish to replace the full match with it's value converted to uppercase.
    sbTemp.ToUppercase()
    json.UpdateSb("match[i].group[0].rep",sbTemp)

    i = i + 1
End While

' The JSON now has replacement strings:
Debug.WriteLine(json.Emit())

' {
'   "match": [
'     {
'       "group": [
'         {
'           "cap": "John Anders",
'           "idx": 0,
'           "len": 11,
'           "rep": "JOHN ANDERS"
'         }
'       ]
'     },
'     {
'       "group": [
'         {
'           "cap": "Mary Robins",
'           "idx": 19,
'           "len": 11,
'           "rep": "MARY ROBINS"
'         }
'       ]
'     }
'   ]
' }

' Call RegexReplace to update the StringBuilder with the replacements.
success = sb.RegexReplace(json)
If (success = False) Then
    Debug.WriteLine(sb.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Result after doing replacements:")
Debug.WriteLine(sb.GetAsString())

' Result after doing replacements:
' JOHN ANDERS, +_+_+ MARY ROBINS $$$$