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C++ Academy · Lesson

Search and Replace

Transform text with regex.

regex_replace

std::regex_replace returns a new string where every match of a pattern is replaced by a replacement string.

  • The original string is left unchanged.
  • By default, all matches are replaced.
#include <iostream>
#include <regex>

int main() {
    std::regex p("cat");
    std::string s = "the cat and the cat";
    std::cout << std::regex_replace(s, p, "dog") << '\n';
    return 0;
}

Replacing Digits

Patterns make bulk edits easy, such as masking every digit in a string with a placeholder.

#include <iostream>
#include <regex>

int main() {
    std::regex p("\\d");
    std::string s = "PIN 1234";
    std::cout << std::regex_replace(s, p, "*") << '\n';
    return 0;
}

All lessons in this course

  1. regex Basics
  2. Capturing Groups
  3. Search and Replace
  4. Performance Notes
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