How to Format a String Without Printing in Golang

The Printf is arguably the most common implementation of any variable formatted as a string. Golang has a simple technique of formatting a string without printing it.

The Sprintf() function of the fmt package in Go can be used to do this. The sole difference between Printf() & Sprintf() is Printf() formats and prints the message, whereas Sprintf() merely formats the message.

Use the Sprintf() Function to Format a String in Golang

The formatting functions format the string based on the format specifiers sent to them.

package main

import (
	"fmt"
)

func main() {
	name := "Jay"
	age := 23

	res := fmt.Sprintf("%s is %d years old", name, age)
	fmt.Println(res)
}

Output:

Jay is 23 years old

Another example is the sprintf() method in the fmt package formats a string and returns the output string.

package main

import (
	"fmt"
)

func main() {
	name := "Jay"
	country := "India"

	str := fmt.Sprintf("%s is from %s\n", name, country)

	fmt.Println(str)

	name = "Mike"
	age := 20

	str = fmt.Sprintf("%s is %d\n", name, age)

	fmt.Println(str)
}

Output:

Jay is from India

Mike is 20

This last example demonstrates how to rearrange the format specifiers.

package main

import (
	"fmt"
)

func main() {
	a := 2
	b := 3
	c := 4

	res := fmt.Sprintf("There are %d grapes, %d bananas, and %d strawberries.", a, b, c)
	fmt.Println(res)
}

Output:

There are 2 grapes, 3 bananas, and 4 strawberries.