Formatting Strings in Go

Go follows the printf tradition from the C language. In my opinion, string formatting/interpolation in Go is currently less elegant than JavaScript and Python.

• fmt.Printf - Prints a formatted string to standard out.
• fmt.Sprintf() - Returns the formatted string

Examples

%v - Interpolate the default representation

The %v variant prints the Go syntax representation of a value. You can usually use this if you're unsure what else to use. That said, it's better to use the type-specific variant if you can.

fmt.Printf("I am %v years old", 10)
// I am 10 years old

fmt.Printf("I am %v years old", "way too many")
// I am way too many years old

%s - Interpolate a string

fmt.Printf("I am %s years old", "way too many")
// I am way too many years old

%d - Interpolate an integer in decimal form

fmt.Printf("I am %d years old", 10)
// I am 10 years old

%f - Interpolate a decimal

fmt.Printf("I am %f years old", 10.523)
// I am 10.523000 years old

// The ".2" rounds the number to 2 decimal places
fmt.Printf("I am %.2f years old", 10.523)
// I am 10.53 years old

If you're interested in all the formatting options, feel free to take a look at the fmt package's docs here.

Assignment

Create a new variable called msg on line 9. It's a string that contains the following:

Hi NAME, your open rate is OPENRATE percent

Where NAME is the given name, and OPENRATE is the openRate rounded to the nearest "tenths" place.