How to find the Index of Substring in Rust - Step by Step Examples

◀ Previous Next ▶

How to find the Index of Substring in Rust ?

Answer

To find the index of a substring in Rust, you can use the find method of the str type.

✐ Examples

1 Find Index of Substring in String

In this example,

We create a string variable named str with a string value.
We use the find method of str to find the index of a specific substring within str.
The find method returns an Option, which is Some(index) if the substring is found, and None otherwise.
Finally, we handle the result to print the index if found.

Rust Program

fn main() {
    let str = "Hello World";
    if let Some(index) = str.find("World") {
        println!("Index of substring is: {}", index);
    } else {
        println!("Substring not found!");
    }
}

Output

Index of substring is: 6

2 Find Index of Substring in Another String

In this example,

We create two string variables named str1 and str2 with different values.
We use the find method of str1 to find the index of str2 within str1.
The find method returns an Option, which is Some(index) if the substring is found, and None otherwise.
Finally, we handle the result to print the index if found.

Rust Program

fn main() {
    let str1 = "apple banana cherry banana";
    let str2 = "cherry";
    if let Some(index) = str1.find(str2) {
        println!("Index of substring is: {}", index);
    } else {
        println!("Substring not found!");
    }
}

Output

Index of substring is: 13

Summary

In this tutorial, we learned How to find the Index of Substring in Rust language with well detailed examples.

◀ Previous Next ▶

Rust Tutorials

Rust How-Tos

How to find the Index of Substring in Rust - Step by Step Examples

How to find the Index of Substring in Rust ?

Answer

✐ Examples

1 Find Index of Substring in String

Rust Program

Output

2 Find Index of Substring in Another String

Rust Program

Output

Summary

More Rust Strings Tutorials