是否可以在Golang中的一次操作中提取字符串的一部分并替换这些部分？

Question

Say I want to extract all numbers from a string (Most likely using regex matching) and I also want to replace those number matches with a generic placeholder like "#".

This is easily done in two parts using FindAll, then ReplaceAll. However I have serious doubts about the performance costs of doing such operations.

So take a string

"sdasd 3.2% sadas 6 ... +8.9"

replace it with

"sdasd #% sadas # ... +#"

and get a slice

[3.2,6.0,8.9]

In the most performant way possible.

Edit : I implemented the regexp.FindAllString + regexp.ReplaceAllString and the performance hit to my app was very minimal. I will hopefully try Elliot Chance's approach and compare the two when I have time.

Answer 1

If you need raw performance than regexp is rarely the way to achieve it, even if it is convenient. Iterating token by token should be pretty fast. Some code:

input := "sdasd 3.2 sadas 6"
output := []string{}
numbers := []float64{}

for _, tok := range strings.Split(input, " ") {
    if f, err := strconv.ParseFloat(tok, 64); err == nil {
        numbers = append(numbers, f)
        tok = "#"
    }
    output = append(output, tok)
}
finalString := strings.Join(output, " ")
fmt.Println(finalString, numbers)

playground link

I'm sure there's a few more optimizations in there that could be made, but this is the general approach I'd take.