Remove HTML

Suppose a string in a Go program contains HTML markup, but we do not want to keep the markup. We can remove the tags with a for-loop.

With a rune slice, we can build up the runes for the result. We detect markup by testing each rune in the original string for angle brackets.

Example

We introduce the stripHtml function, which receives a string and returns another string. We call stripHtml to test in the main() function.

package main

import (
    "fmt"
)

func stripHtml(source string) string {
    data := []rune{}
    inside := false
    // Step 1: loop over string with range loop.
    for _, c := range source {
        if c == '<' {
            inside = true
            continue
        }
        if c == '>' {
            inside = false
            continue
        }
        // Step 2: append chars not inside markup tags starting and ending with brackets.
        if !inside {
            data = append(data, c)
        }
    }
    // Step 3: return string based on the rune slice.
    return string(data)
}

func main() {
    // Call the stripHtml function.
    input := "<p>Hello <b>world</b>!</p>"
    result := stripHtml(input)
    fmt.Println(input)
    fmt.Println(result)
}
<p>Hello <b>world</b>!</p>
Hello world!

In the results, we can see that the "p" and "b" tags were removed from the markup. Note that this function will fail for HTML comments—a more powerful parser would be needed.

Summary

It is possible to use regular expressions to remove markup from strings, but this offers little advantage over a for-loop. And it is usually slower.