What is the string.replacen() method in Rust?

Overview

The replacen() method replaces the first n matches of a substring in a string. If we specify a match and several matches are found, we can specify the number of matches to replace.

Syntax

string.replacen(match, substring, n)
Syntax of the replacen() method in Rust

Parameters

match: This is the match we want to find and replace.

substring: This is the replacement for the match if it's found.

n: This represents the first n number of matches to replace in string. .

Return value

The replacen() method returns a new string in which all the specified and found matches have been replaced.

Example

fn main() {
  // create some strings
  let str1 = "me you me I we me";
  let str2 = "Rust Java Java Rust Rust";
  let str3 = "foo bar bar bar bar foo bar bar";
  // replace some matches
  println!("{}", str1.replacen("me", "myself", 2));        // replace first two "me"s
  println!("{}", str2.replacen("Java", "JavaScript", 1));  // replace first one "Java"
  println!("{}", str3.replacen("bar", "baz", 3));          // replace first three "foo"s
}

Explanation

  • Lines 3–5: We declare and initialize three strings: str1, str2, and str3.
  • Lines 8–10: We use the replacen() method to replace the specified matches found in the respective strings, and print the results to the console.

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