Golang: Print

Print

Use the package fmt

fmt.Printf("there are %v apples\n", 3)

The first argument is a string. The string can contain many special placeholder characters , starting with the percent character %.

Second argument and rest arguments are used to fill the placeholders.

Example:
fmt.Printf("Name is %v, Age is %v \n", "john", 36)

package main

import "fmt"

func main() {

	var x = "John"
	var y = 36

	fmt.Printf("name is %v, age is %v\n", x, y)
	// name is John, age is 36

}

Here's the most useful placeholders:

%v

Any value. Print in human readable form.

%#v

Print in golang syntax

%+v

If value is struct, also show the field names.

%T

Type of the value

%%

A literal percent sign

Print Line

For quick printing, use

fmt.Println(v1, v2 etc)

it's similar to fmt.Printf with "%v" for format.

package main

import "fmt"

func main() {

	var x = 3
	var y = 4
	fmt.Println(x, y) // 3 4
}

Convert to String

To convert a value to string, use

fmt.Sprintf(string, v1, v2 etc)

it return a string.

package main

import "fmt"

func main() {

	var x = "John"
	var y = 36

	var s = fmt.Sprintf("name is %v, age is %v\n", x, y)

	fmt.Println(s)
	// name is John, age is 36
}

Example: Print Type

It is very useful to print the type of a value, when learning go.

fmt.Printf("%T\n", val)

package main

import "fmt"

// using Printf to show different types of value

func main() {

	var x = 3
	fmt.Printf("%v\n", x) // 3
	fmt.Printf("%T\n", x) // int

	var x2 = 3.4
	fmt.Printf("%v\n", x2) // 3.4
	fmt.Printf("%T\n", x2) // float64

}

Print String as Sequence of Byte/Char/Codepoint

Golang: Print String

Print Slice

Golang: Slice

Print Struct

Golang: Struct