daytime, _ := time.Parse("2006-01-02", day)
var weekday = daytime.Weekday()
fmt.Println(weekday, int(daytime.Weekday()), daytime.Weekday())

Output : Friday 5 Friday

感觉输出好诡异，明明是一个Int类型，为何不强转的情况下是个string形式的输出。

Weekday的类型源码定义

type Weekday int

const (
    Sunday Weekday = iota
    Monday
    Tuesday
    Wednesday
    Thursday
    Friday
    Saturday
)

time中的Weekday()方法源码

// Weekday returns the day of the week specified by t.
func (t Time) Weekday() Weekday {
    return absWeekday(t.abs())
}

// absWeekday is like Weekday but operates on an absolute time.
func absWeekday(abs uint64) Weekday {
    // January 1 of the absolute year, like January 1 of 2001, was a Monday.
    sec := (abs + uint64(Monday)*secondsPerDay) % secondsPerWeek
    return Weekday(int(sec) / secondsPerDay)
}

真感觉好诡异，始终是ToYoung😳