convert 12 hour format to 24 hour format time in golang

For example,

package main

import (
    "fmt"
    "time"
)

func main() {
    layout1 := "03:04:05PM"
    layout2 := "15:04:05"
    t, err := time.Parse(layout1, "07:05:45PM")
    if err != nil {
        fmt.Println(err)
        return
    }
    fmt.Println(t.Format(layout1))
    fmt.Println(t.Format(layout2))
}

Playground: https://play.golang.org/p/Ypn2-lEF_Zs

Output:

07:05:45PM
19:05:45

---

Reference: package time

The key is to understand how to write the layout argument. According to godoc, the reference time for layout is:

Mon Jan 2 15:04:05 -0700 MST 2006

Each string element of a date has a specific numerical value relevant to it:

You need to rewrite this date to your format as the layout for parse. You only need to include the elements to your need. So only the hour, minute, second and AM/PM is important. Reference time 15:04:05 should be written as 03:04:05PM.

Just use the rewritten time as the layout parameter:

import time

...


t, _ := time.Parse("03:04:05PM", "07:05:45PM")
fmt.Println(t.Format("15:04:05"))

Output:

19:05:45