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

C++

#include <CkStringBuilder.h>
#include <CkJsonObject.h>

void ChilkatSample(void)
    {
    bool success = false;

    success = false;

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

    CkStringBuilder sb;
    sb.Append(subject);

    CkJsonObject json;
    json.put_EmitCompact(false);

    int timeoutMs = 2000;
    int numMatches = sb.RegexMatch(pattern,json,timeoutMs);
    if (numMatches < 0) {
        // Probably an error in the regular expression.
        // Suggestion: Use AI to help create and/or diagnose regular expressions.
        std::cout << sb.lastErrorText() << "\r\n";
        return;
    }

    // Examine the matches:
    std::cout << json.emit() << "\r\n";

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

    CkStringBuilder sbTemp;

    int i = 0;
    numMatches = json.SizeOfArray("match");
    while (i < numMatches) {

        json.put_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;
    }

    // The JSON now has replacement strings:
    std::cout << json.emit() << "\r\n";

    // {
    //   "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) {
        std::cout << sb.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Result after doing replacements:" << "\r\n";
    std::cout << sb.getAsString() << "\r\n";

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