Delphi ActiveX

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

Delphi ActiveX

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Integer;
subject: WideString;
pattern: WideString;
sb: TChilkatStringBuilder;
json: TChilkatJsonObject;
timeoutMs: Integer;
numMatches: Integer;
sbTemp: TChilkatStringBuilder;
i: Integer;

begin
success := 0;

success := 0;

subject := 'John Anders, +_+_+ Mary Robins $$$$';
pattern := '\\w+\\s+\\w+';

sb := TChilkatStringBuilder.Create(Self);
sb.Append(subject);

json := TChilkatJsonObject.Create(Self);
json.EmitCompact := 0;

timeoutMs := 2000;
numMatches := sb.RegexMatch(pattern,json.ControlInterface,timeoutMs);
if (numMatches < 0) then
  begin
    // Probably an error in the regular expression.
    // Suggestion: Use AI to help create and/or diagnose regular expressions.
    Memo1.Lines.Add(sb.LastErrorText);
    Exit;
  end;

// Examine the matches:
Memo1.Lines.Add(json.Emit());

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

sbTemp := TChilkatStringBuilder.Create(Self);

i := 0;
numMatches := json.SizeOfArray('match');
while i < numMatches do
  begin

    json.I := i;

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

    // 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.ControlInterface);

    i := i + 1;
  end;

// The JSON now has replacement strings:
Memo1.Lines.Add(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.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(sb.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('Result after doing replacements:');
Memo1.Lines.Add(sb.GetAsString());

// Result after doing replacements:
// JOHN ANDERS, +_+_+ MARY ROBINS $$$$
end;