`Remove` HTML

Sometimes a string has HTML characters in it that are not desired—they may have been entered by mistake. It is straightforward to remove common HTML tags with a Rust function.

By checking each character for the angle brackets, we can detect when markup starts and ends. Then we can avoid adding those characters to a string copy.

To begin, we introduce a strip_html function that receives a str reference, and returns a new string. The result of this function is a string with no HTML markup.

Step 1 We use a for-loop over the chars in the string. Chars() returns an iterator of the individual characters.

Step 2 We detect the angle brackets and set a local flag variable to true or false based on whether we are inside a markup region.

Step 3 Here we reach characters that are not part of a markup region, so we add them to our resulting string.

Step 4 We return the string. This contains all characters in the source string excluding markup regions.

fn strip_html(source: &str) -> String {
    let mut data = String::new();
    let mut inside = false;
    // Step 1: loop over string chars.
    for c in source.chars() {
        // Step 2: detect markup start and end, and skip over markup chars.
        if c == '<' {
            inside = true;
            continue;
        }
        if c == '>' {
            inside = false;
            continue;
        }
        if !inside {
            // Step 3: push other characters to the result string.
            data.push(c);
        }
    }
    // Step 4: return string.
    return data;
}

fn main() {
    // Use the strip html function to remove markup.
    let input = "<p>Hello <b>world</b>!</p>";
    let result = strip_html(input);
    println!("{input}");
    println!("{result}");
}<p>Hello <b>world</b>!</p>
Hello world!

Results

It is easy to determine that the function correctly removes simple HTML tags. A problem would be tags inside of HTML comments—a more complex function would be needed to support this.

It is possible to remove HTML tags from a string in Rust, and regular expressions are not needed. The code is small and easy to maintain.

Remove HTML

Results

`Remove` HTML