Printf中的％g没有给出固定的小数位数，例如％f或％e

Question

According to these docs %g is %e for large exponents, %f otherwise. However, when I do:

package main

import "fmt"

func main() {
    var a float64 = 2.0
    fmt.Printf("%f
", a)
    fmt.Printf("%e
", a)
    fmt.Printf("%g
", a)
}

I get:

2.000000
2.000000e+00
2

Why does the output for %g not contain fixed decimal places like %e or %f?

Answer 1

Package fmt

Printing

The default precision for %g is the smallest number of digits necessary to identify the value uniquely

For the value 2.0 that is one digit giving the value 2.