Splitting a string at Space, except inside quotation marks - string

Question

I was wondering if there is any way I could easily split a string at spaces, except when the space is inside quotation marks?
For example, changing
Foo bar random "letters lol" stuff
into
Foo, bar, random, "letters lol", stuff

Answer 1

Think about it. You have a string in comma separated values (CSV) file format, RFC4180, except that your separator, outside quote pairs, is a space (instead of a comma). For example,
package main
import (
"encoding/csv"
"fmt"
"strings"
)
func main() {
s := `Foo bar random "letters lol" stuff`
fmt.Printf("String:\n%q\n", s)
// Split string
r := csv.NewReader(strings.NewReader(s))
r.Comma = ' ' // space
fields, err := r.Read()
if err != nil {
fmt.Println(err)
return
}
fmt.Printf("\nFields:\n")
for _, field := range fields {
fmt.Printf("%q\n", field)
}
}
Playground: https://play.golang.org/p/Ed4IV97L7H
Output:
String:
"Foo bar random \"letters lol\" stuff"
Fields:
"Foo"
"bar"
"random"
"letters lol"
"stuff"

Answer 2

Using strings.FieldsFunc try this:
package main
import (
"fmt"
"strings"
)
func main() {
s := `Foo bar random "letters lol" stuff`
quoted := false
a := strings.FieldsFunc(s, func(r rune) bool {
if r == '"' {
quoted = !quoted
}
return !quoted && r == ' '
})
out := strings.Join(a, ", ")
fmt.Println(out) // Foo, bar, random, "letters lol", stuff
}
Using simple strings.Builder and range over string and keeping or not keeping " at your will, try this
package main
import (
"fmt"
"strings"
)
func main() {
s := `Foo bar random "letters lol" stuff`
a := []string{}
sb := &strings.Builder{}
quoted := false
for _, r := range s {
if r == '"' {
quoted = !quoted
sb.WriteRune(r) // keep '"' otherwise comment this line
} else if !quoted && r == ' ' {
a = append(a, sb.String())
sb.Reset()
} else {
sb.WriteRune(r)
}
}
if sb.Len() > 0 {
a = append(a, sb.String())
}
out := strings.Join(a, ", ")
fmt.Println(out) // Foo, bar, random, "letters lol", stuff
// not keep '"': // Foo, bar, random, letters lol, stuff
}
Using scanner.Scanner, try this:
package main
import (
"fmt"
"strings"
"text/scanner"
)
func main() {
var s scanner.Scanner
s.Init(strings.NewReader(`Foo bar random "letters lol" stuff`))
slice := make([]string, 0, 5)
tok := s.Scan()
for tok != scanner.EOF {
slice = append(slice, s.TokenText())
tok = s.Scan()
}
out := strings.Join(slice, ", ")
fmt.Println(out) // Foo, bar, random, "letters lol", stuff
}
Using csv.NewReader which removes " itself, try this:
package main
import (
"encoding/csv"
"fmt"
"log"
"strings"
)
func main() {
s := `Foo bar random "letters lol" stuff`
r := csv.NewReader(strings.NewReader(s))
r.Comma = ' '
record, err := r.Read()
if err != nil {
log.Fatal(err)
}
out := strings.Join(record, ", ")
fmt.Println(out) // Foo, bar, random, letters lol, stuff
}
Using regexp, try this:
package main
import (
"fmt"
"regexp"
"strings"
)
func main() {
s := `Foo bar random "letters lol" stuff`
r := regexp.MustCompile(`[^\s"]+|"([^"]*)"`)
a := r.FindAllString(s, -1)
out := strings.Join(a, ", ")
fmt.Println(out) // Foo, bar, random, "letters lol", stuff
}

Answer 3

You could use regex
This (go playground) will cover all use cases for multiple words inside quotes and multiple quoted entries in your array:
package main
import (
"fmt"
"regexp"
)
func main() {
s := `Foo bar random "letters lol" stuff "also will" work on "multiple quoted stuff"`
r := regexp.MustCompile(`[^\s"']+|"([^"]*)"|'([^']*)`)
arr := r.FindAllString(s, -1)
fmt.Println("your array: ", arr)
}
Output will be:
[Foo, bar, random, "letters lol", stuff, "also will", work, on, "multiple quoted stuff"]
If you want to learn more about regex here is a great SO answer with super handy resources at the end - Learning Regular Expressions
Hope this helps