转到-如何格式化数字位数

Question

How can I format an int in go to make sure there is always two digits? For example, 1 would be formatted to 01.

Answer 1

You can use fmt.Printf() or fmt.Sprintf() to create a string with left-padded zeroes. fmt.Printf() will print the data while fmt.Sprintf() will allow you to assign the resulting string to a variable.

Here are the signatures from the docs:

func Printf(format string, a ...interface{}) (n int, err error)

func Sprintf(format string, a ...interface{}) string

For example:

// Printing directly using fmt.Printf()
fmt.Printf("%02d
", 1)

// With output assignment
count, err := fmt.Printf("%02d
", 1)
if err == nil {
    fmt.Printf("Printed %v bytes
", count)
} else {
    fmt.Println("Error printing")
}

// Assigning to variable using fmt.Sprintf()
formatted := fmt.Sprintf("%02d", 1)
fmt.Println(formatted)

Docs: https://golang.org/pkg/fmt/