Rust Tutorials

How to Replace a Substring in a String using Regular Expression in Rust

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How to Replace a Substring in a String using Regular Expression in Rust ?

Answer

To replace all occurrences of a substring in a string using regular expression in Rust, you can use the regex crate.

✐ Examples

1 Replace Substring "Hello" with "Hi"

In this example,

We add the regex crate to the dependencies in Cargo.toml.
We use the regex::Regex struct to create a regular expression pattern matching "Hello".
We use the replace_all method to replace all occurrences of the pattern with "Hi".
Finally, we print the modified string.

Rust Program

[dependencies]
regex = "1.5.4"

fn main() {
    let str = "Hello World Hello";
    let re = regex::Regex::new("Hello").unwrap();
    let new_str = re.replace_all(str, "Hi");
    println!("{}", new_str);
}

Output

Hi World Hi

2 Replace Digits with 'Y'

In this example,

We add the regex crate to the dependencies in Cargo.toml.
We use the regex::Regex struct to create a regular expression pattern matching digits (\d).
We use the replace_all method to replace all occurrences of the pattern with 'Y'.
Finally, we print the modified string.

Rust Program

[dependencies]
regex = "1.5.4"

fn main() {
    let str = "Hello123World789";
    let re = regex::Regex::new(r"\d").unwrap();
    let new_str = re.replace_all(str, "Y");
    println!("{}", new_str);
}

Output

HelloYYYWorldYYY

Summary

In this tutorial, we learned How to Replace a Substring in a String using Regular Expression in Rust language with well detailed examples.

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How to Replace a Substring in a String using Regular Expression in Rust

How to Replace a Substring in a String using Regular Expression in Rust ?

Answer

✐ Examples

1 Replace Substring "Hello" with "Hi"

Rust Program

Output

2 Replace Digits with 'Y'

Rust Program

Output

Summary

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