meet it

fills in the gaps in a sentence.

fmt.Printf fills in a sentence for you. Write the text with %v wherever a value should go, then list the values after commas. Each %v is a , and they are filled in order.

Printf does not move to a new line on its own, so end the text with \n, which means new line. works the same way but hands the text back, ready to store in a box.

To join a number onto a string with +, turn it into text first. The toolbox does that: strconv.Itoa(10) hands back "10".

package main
import "fmt"
import "strconv"
func main() {
	name := "Ava"
	score := 42
	fmt.Printf("%v scored %v points\n", name, score)
	label := fmt.Sprintf("Player: %v", name)
	fmt.Println(label)
	fmt.Println("Score: " + strconv.Itoa(score))
}

Itoa is short for "integer to ASCII", an old way of saying number to text.

guess first

The values go in order. What will this show?

Guess before you run it. Wrong guesses are how you learn, and nothing is marked.

package main
import "fmt"
func main() {
	fmt.Printf("%v has %v cats\n", 3, "Leo")
}

your turn

Your turn. How hungry are you?

Type a food between the quotes and a whole number after count :=. Then press run to see Printf fill the gaps.

Your code

output

press run to see what happens

fix it

Go will not join this number. Can you fix it?

Broken code to fix

output

press run to see what happens

Read the error. Go cannot use + with a string and an int together.
Let Printf slot the number into the sentence with a %v placeholder instead.
Change line 5 to fmt.Printf("You reached level %v\n", level), then press run.

nailed it

you slotted values into sentences. :D

Printf fills each %v placeholder with a value, in order.
End Printf text with \n to start a new line.
strconv.Itoa turns a number into text.

new words in your collection

Printf
placeholder
Sprintf
strconv

This lesson isn’t saved. A free account remembers every lesson you finish.

fmt.Printf fills in the gaps in a sentence.

The values go in order. What will this show?

Your turn. How hungry are you?

Go will not join this number. Can you fix it?

you slotted values into sentences. :D

fills in the gaps in a sentence.