Iterating over Go string to extract specific substrings

Question

I started learning Go and I want to implement some algorithm. I want to iterate over a string and then extract some substrings for example : p -(40) *(GOT) +(FF) should return an array like this: [p, 40, GOT, FF]

I wrote something like this but it's vague:

import (
    "strings"

) 

func find(input string){
    var result []string
    a := strings.SplitN(input, "-(", 2);
    result[0] = a[0]
    b := strings.SplitN(a[1], ") *(", 2)
    result[1] = b[0]
    c := strings.SplitN(a[1], ") +(", 2)
    result[2] = c[0]
    d := strings.SplitN(a[1], ")", 2)
    result[3] = d[0]
}

Can someone please correct me or suggest something easier? Thanks!

Thanks for the reply! kinda hard for me, I'm a noobie in programmation.. — jiji, Aug 22 '16 at 15:08

score 1 · Accepted Answer · 2016-08-22T15:27:40.343

You may use strings.FieldsFunc, like this working sample code:

package main

import "fmt"
import "strings"

func find(input string) []string {
    return strings.FieldsFunc(input, split)
}

func main() {
    strs := find("p -(40) *(GOT) +(FF)")
    str := strings.Replace(fmt.Sprint(strs), " ", ", ", -1)
    fmt.Println(str)
}

func split(r rune) bool {
    return r == ' ' || r == '-' || r == '(' || r == ')' || r == '*' || r == '+'
}

output:

[p, 40, GOT, FF]

You may use strings.Fields then strings.Trim, like this working sample code:

package main

import "fmt"
import "strings"

func main() {
    fmt.Println(find("p -(40) *(GOT) +(FF)"))
}

func find(input string) []string {
    strs := strings.Fields(input)
    result := make([]string, 0, len(strs))

    for _, v := range strs {
        s := strings.Trim(v, "()+-*")
        if len(s) > 0 {
            result = append(result, s)
        }
    }
    return result
}

output:

[p 40 GOT FF]

Also this works for your special case:

package main

import "fmt"
import "strings"

func main() {
    fmt.Println(find("p -(40) *(GOT) +(FF)"))
}

func find(input string) []string {
    strs := strings.Fields(input)
    for i := 0; i < len(strs); i++ {
        strs[i] = strings.Trim(strs[i], "()+-*")
    }
    return strs
}

output:

[p 40 GOT FF]

And if you need output like this string: [p, 40, GOT, FF], try this working sample code:

package main

import "fmt"
import "strings"

func main() {
    strs := find("p -(40) *(GOT) +(FF)")
    str := strings.Replace(fmt.Sprint(strs), " ", ", ", -1)
    fmt.Println(str)
}

func find(input string) []string {
    strs := strings.Fields(input)
    for i := 0; i < len(strs); i++ {
        strs[i] = strings.Trim(strs[i], "()+-*")
    }
    return strs
}

output:

[p, 40, GOT, FF]

I was wondering why did u choose 0 as length of the slices in result := make([]string, 0, len(strs)) ? Thanks — jiji, Aug 24 '16 at 09:58
@jiji see detailed answer here: http://stackoverflow.com/a/39121360/6169399 — , Aug 24 '16 at 10:59

Iterating over Go string to extract specific substrings

1 Answers1