在Go中格式化详细日期

Question

I would like to produce formatted dates in a human-readable format. Typically in an English locale, suffixes are used for the day of the month, i.e. 1st, 2nd, 3rd, 4th, 5th and so on.

I tried using the format string "Monday 2nd January" to format such dates but it doesn't appear to work.

E.g. in the playground:

import (
    "fmt"
    "time"
)

const format = "Monday 2nd January"

func main() {
    t1 := time.Date(2015, 3, 4, 1, 1, 1, 1, time.UTC)
    fmt.Println(t1.Format(format))

    t2 := time.Date(2015, 3, 1, 1, 1, 1, 1, time.UTC)
    fmt.Println(t2.Format(format))
}

This generates the result

Wednesday 4nd March
Sunday 1nd March

but I would expect

Wednesday 4th March
Sunday 1st March

What have I done wrong?

Answer 1

It doesn't support that kind of formatting, you will have to implement it yourself, something (hacky) like this:

func formatDate(t time.Time) string {
    suffix := "th"
    switch t.Day() {
    case 1, 21, 31:
        suffix = "st"
    case 2, 22:
        suffix = "nd"
    case 3, 23:
        suffix = "rd"
    }
    return t.Format("Monday 2" + suffix + " January")
}

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