Variable capturing in string literal in Go?

Question

In Ruby, I could directly capture variables in string literals like in bash.

SRCDIR  =   "aaa"
DSTDIR  =   "bbb"

puts "SRCDIR = #{SRCDIR}"
puts "DSTDIR = #{DSTDIR}"

This is a simple and tiny feature, but very nice to make it feel like a shell script. If I have to write a complex shell script this helps a lot because this eliminates the need for substitution, concatenation and format expression.

Does Go have something like this? If it does, how to use it?

Check out the package text/template if you are looking to produce parameterized text. — Dmitri Goldring
– Dmitri Goldring, Commented Jan 22, 2014 at 14:14

Eve Freeman · Accepted Answer · 2014-01-22 01:26:03Z

5

Not without a formatting string; the usual way to do this is with fmt.Printf or fmt.Sprintf:

srcdir := "aaa"
dstdir := "bbb"

// separated out Sprintf and Println for clarity
fmt.Println(fmt.Sprintf("SRCDIR = %s", srcdir))
fmt.Println(fmt.Sprintf("DSTDIR = %s", dstdir))

// could be shortened if you're just printing them
fmt.Printf("SRCDIR = %s\n", srcdir)
fmt.Printf("DSTDIR = %s\n", dstdir)

answered Jan 22, 2014 at 1:26

Eve Freeman

33.3k5 gold badges89 silver badges104 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Not_a_Golfer Over a year ago

Also worth noting that you can specify index positions in your string and not format in the exact same order of your parameters. e.g. - fmt.Printf("dstdir=%[2]s srcdir=%[1]s", srcdir, dstdir)

Flavio · Accepted Answer · 2020-06-22 16:44:38Z

1

You have to concat with the + operator as in JS

main.go

package main

import "fmt"

func main() {

    movieQuote := `"What's the most you ever lost on a coin toss?"`
    statement := `Back-ticks allow double quotes, ` + movieQuote + `, and single quote apostrophe's`

    fmt.Println("movieQuote: ", movieQuote)
    fmt.Println("statement: ", statement)
}

Run

go run main.go

Output:

movieQuote:  "What's the most you ever lost on a coin toss?"
statement:  Back-ticks allow double quotes, "What's the most you ever lost on a coin toss?", and single quote apostrophe's

edited Jun 22, 2020 at 16:44

answered May 25, 2020 at 6:57

Flavio

6265 silver badges10 bronze badges

Comments

kostix · Accepted Answer · 2014-01-22 14:34:02Z

0

What Wes said. I should add that if you're using custom types, you might define a method which has the signature String() string on them (to essentially make them satisfy the fmt.Stringer interface) and then pass instances of these types directly to functions of the fmt package which expect a string, such as fmt.Println(). A simple introduction to this might be found in "Effective Go".

answered Jan 22, 2014 at 14:34

kostix

56.2k14 gold badges104 silver badges188 bronze badges

Comments

Flavio · Accepted Answer · 2020-06-22 17:10:20Z

GQL Queries

package main

import (
    "github.com/gookit/color"
)

const (
    offerInfo string = `{
        id
        name
        description
        logoURL
        opt_ins {
          id
          name
          description
        }
      }`
)

func QueryAllOffers() string {
    return `{ offer ` + offerInfo + `}`
}

func QueryOfferByID(id string) string {
    return `{
        offer (id: "` + string(id)  + `")` + offerInfo + ` }`
}

func main() {
    queryAllOffers := QueryAllOffers()
    color.Cyan.Println(queryAllOffers)

    offerID := "0001"
    queryOfferByID := QueryOfferByID(offerID)
    color.Blue.Println(queryOfferByID)
}

Output: queryAllOffers

{
  offer {
    id
    name
    description
    logoURL
    opt_ins {
      id
      name
      description
    }
  }
}

Output: queryOfferById

{
  offer(id: "0001") {
    id
    name
    description
    logoURL
    opt_ins {
      id
      name
      description
    }
  }
}

Collectives™ on Stack Overflow

Variable capturing in string literal in Go?

4 Answers 4

1 Comment

Comments

Comments

GQL Queries

Output: queryAllOffers

Output: queryOfferById

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

1 Comment

Comments

Comments

GQL Queries

Output: queryAllOffers

Output: queryOfferById

Comments

Your Answer

Sign up or log in

Post as a guest

Related