What would be a non-regexp alternative?

[Vivi]

I find there're large chuck of strings would need to be scanned and remove/clean up, are there alternative way to improve beside using regexp? Replacer/NewReplacer seems to be limit on exact characters or my idea of NewReplaceGroup could be useful.

([abc .#$]+)

[Tamás Gulácsi]

You just want to remove those characters? Use strings.Map.

[Vivi]

I like to replace one or more characters to one character e.g. to sanitize proper slug title with a dash.

[Tamás Gulácsi]

See https://play.golang.org/p/dI6ZFG_mzLV for example.

[Vivi]

Interesting, I didn't know strings.Map could work this way, I have done a performance benchmark with PHP 7 Pcre2 C is 1,020 nanoseconds and strings.Map version is 2,888 nanoseconds, not bad improvement over regexp. If there is a better approach, however, Rust Re2 is just as fast as PHP Pcre2.

[Tamás Gulácsi]

bytes.Map may be faster.

But even that is just a handful of lines (https://github.com/golang/go/blob/go1.14.2/src/bytes/bytes.go#L453)

so if you really want speed, just copy and tweak it.

I'm not saying that regexps are slow, but they're complex, and where

a simple loop with a boolean placeholder satisfies, then we don't need  that regexp.