Time Formatting in Golang

Golang supports time formatting and parsing via pattern-based layouts. To format time, we use the Format() method which formats a time.Time object.

Syntax:

func (t Time) Format(layout string) string

We can either provide custom format or predefined date and timestamp format constants are also available which are shown as follows.

Format	Example
ANSIC	“Mon Jan _2 15:04:05 2006”
UnixDate	“Mon Jan _2 15:04:05 MST 2006”
RubyDate	“Mon Jan 02 15:04:05 -0700 2006”
RFC822	“02 Jan 06 15:04 MST”
RFC822Z	“02 Jan 06 15:04 -0700”
RFC850	“Monday, 02-Jan-06 15:04:05 MST”
RFC1123	“Mon, 02 Jan 2006 15:04:05 MST”
RFC1123Z	“Mon, 02 Jan 2006 15:04:05 -0700”
RFC3339	“2006-01-02T15:04:05Z07:00”
RFC3339Nano	“2006-01-02T15:04:05.999999999Z07:00”

Layouts must use the reference time Mon Jan 2 15:04:05 MST 2006 to show the pattern with which to format/parse a given time/string.

Example 1:

// Golang program to illustrate the time
// formatting using custom layouts

package main

import (
    "fmt"
    "time"
)

func main() {

    // this function returns the present time
    current_time := time.Now()

    // individual elements of time can
    // also be called to print accordingly
    fmt.Printf("%d-%02d-%02dT%02d:%02d:%02d-00:00\n",
    current_time.Year(), current_time.Month(), current_time.Day(),
    current_time.Hour(), current_time.Minute(), current_time.Second())

    // formatting time using
    // custom formats
    fmt.Println(current_time.Format("2006-01-02 15:04:05"))
    fmt.Println(current_time.Format("2006-January-02"))
    fmt.Println(current_time.Format("2006-01-02 3:4:5 pm"))
}

Output:

2009-11-10T23:00:00-00:00
2009-11-10 23:00:00
2009-November-10
2009-11-10 11:0:0 pm

Example 2:

// Golang program to illustrate the time
// formatting using format constants
package main

import (
    "fmt"
    "time"
)

func main() {

    // this function returns the present time
    current_time := time.Now()

    // using inbuilt format constants
    // shown in the table above
    fmt.Println("ANSIC: ", current_time.Format(time.ANSIC))
    fmt.Println("UnixDate: ", current_time.Format(time.UnixDate))
    fmt.Println("RFC1123: ", current_time.Format(time.RFC1123))
    fmt.Println("RFC3339Nano: ", current_time.Format(time.RFC3339Nano))
    fmt.Println("RubyDate: ", current_time.Format(time.RubyDate))
}

Output:

ANSIC:  Tue Nov 10 23:00:00 2009
UnixDate:  Tue Nov 10 23:00:00 UTC 2009
RFC1123:  Tue, 10 Nov 2009 23:00:00 UTC
RFC3339Nano:  2009-11-10T23:00:00Z
RubyDate:  Tue Nov 10 23:00:00 +0000 2009