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;

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 $$$$