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

Overview

In Rust, the find() method is used to find the first match of a specified character or another string. It returns the byte index of the first character of the specified character or string in the case of a successful match, and None in case of an unsuccessful match.

Syntax

string.find(match)
Syntax for find() method in Rust

Parameters

This method takes two parameters:

  • match: This is the string or character searched for in a string,
  • string: This is the string in which the method searches for match.

Return value

This method returns the byte index of the first character of the match. For example: Some(2), Some(14). For no match, it returns None.

Example

fn main() {
  // create some strings
  let str1 = "Educative is the best platform!";
  let str2 = "Rust";
  let str3 = "Welcome to Edpresso";
  let str4 = "Programming";
  // create the matches
  let match1 = "is";
  let match2 = 'R';
  let match3 = "to";
  let match4 = "23";
  // find the matches and print byte indices
  println!(" {:?}", str1.find(match1));
  println!(" {:?}", str2.find(match2));
  println!(" {:?}", str3.find(match3));
  println!(" {:?}", str4.find(match4));
}

Explanation

  • Lines 3–6: We create some strings.
  • Lines 9–12: We create some more strings that we will search for in the strings created in lines 3–6.
  • Lines 15–18: We use the find() method to check if any matches were found and print the results to the console screen.
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