Objective-C

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

Objective-C

#import <NSString.h>
#import <CkoStringBuilder.h>
#import <CkoJsonObject.h>

BOOL success = NO;

success = NO;

NSString *subject = @"John Anders, +_+_+ Mary Robins $$$$";
NSString *pattern = @"\\w+\\s+\\w+";

CkoStringBuilder *sb = [[CkoStringBuilder alloc] init];
[sb Append: subject];

CkoJsonObject *json = [[CkoJsonObject alloc] init];
json.EmitCompact = NO;

int timeoutMs = 2000;
int numMatches = [[sb RegexMatch: pattern json: json timeoutMs: [NSNumber numberWithInt: timeoutMs]] intValue];
if (numMatches < 0) {
    // Probably an error in the regular expression.
    // Suggestion: Use AI to help create and/or diagnose regular expressions.
    NSLog(@"%@",sb.LastErrorText);
    return;
}

// Examine the matches:
NSLog(@"%@",[json Emit]);

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

CkoStringBuilder *sbTemp = [[CkoStringBuilder alloc] init];

int i = 0;
numMatches = [[json SizeOfArray: @"match"] intValue];
while (i < numMatches) {

    json.I = [NSNumber numberWithInt: i];

    // The full match is always in group 0.
    [sbTemp Clear];
    [json StringOfSb: @"match[i].group[0].cap" sb: 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" sb: sbTemp];

    i = i + 1;
}

// The JSON now has replacement strings:
NSLog(@"%@",[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 == NO) {
    NSLog(@"%@",sb.LastErrorText);
    return;
}

NSLog(@"%@",@"Result after doing replacements:");
NSLog(@"%@",[sb GetAsString]);

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