How to format current time using a yyyyMMddHHmmss format?

Question

Use

fmt.Println(t.Format("20060102150405"))

as Go uses following constants to format date,refer here

const (
    stdLongMonth      = "January"
    stdMonth          = "Jan"
    stdNumMonth       = "1"
    stdZeroMonth      = "01"
    stdLongWeekDay    = "Monday"
    stdWeekDay        = "Mon"
    stdDay            = "2"
    stdUnderDay       = "_2"
    stdZeroDay        = "02"
    stdHour           = "15"
    stdHour12         = "3"
    stdZeroHour12     = "03"
    stdMinute         = "4"
    stdZeroMinute     = "04"
    stdSecond         = "5"
    stdZeroSecond     = "05"
    stdLongYear       = "2006"
    stdYear           = "06"
    stdPM             = "PM"
    stdpm             = "pm"
    stdTZ             = "MST"
    stdISO8601TZ      = "Z0700"  // prints Z for UTC
    stdISO8601ColonTZ = "Z07:00" // prints Z for UTC
    stdNumTZ          = "-0700"  // always numeric
    stdNumShortTZ     = "-07"    // always numeric
    stdNumColonTZ     = "-07:00" // always numeric
    stdFracSecond0    = ".0", ".00" // trailing zeros included
    stdFracSecond9    = ".9", ".99" // trailing zeros omitted
)

This question comes in top of Google search when you find "golang current time format" so, for all the people that want to use another format, remember that you can always call to:

t := time.Now()

t.Year()

t.Month()

t.Day()

t.Hour()

t.Minute()

t.Second()

For example, to get current date time as "YYYY-MM-DDTHH:MM:SS" (for example 2019-01-22T12:40:55) you can use these methods with fmt.Sprintf:

t := time.Now()
formatted := fmt.Sprintf("%d-%02d-%02dT%02d:%02d:%02d",
        t.Year(), t.Month(), t.Day(),
        t.Hour(), t.Minute(), t.Second())

As always, remember that docs are the best source of learning: https://golang.org/pkg/time/

import("time")

layout := "2006-01-02T15:04:05.000Z"
str := "2014-11-12T11:45:26.371Z"
t, err := time.Parse(layout, str)
if err != nil {
    fmt.Println(err)
}
fmt.Println(t)

gives:

>> 2014-11-12 11:45:26.371 +0000 UTC

Time package in Golang has some methods that might be worth looking.

func (Time) Format

func (t Time) Format(layout string) string Format returns a textual representation of the time value formatted according to layout, which defines the format by showing how the reference time,

Mon Jan 2 15:04:05 -0700 MST 2006 would be displayed if it were the value; it serves as an example of the desired output. The same display rules will then be applied to the time value. Predefined layouts ANSIC, UnixDate, RFC3339 and others describe standard and convenient representations of the reference time. For more information about the formats and the definition of the reference time, see the documentation for ANSIC and the other constants defined by this package.

Source (http://golang.org/pkg/time/#Time.Format)

I also found an example of defining the layout (http://golang.org/src/pkg/time/example_test.go)

func ExampleTime_Format() {
        // layout shows by example how the reference time should be represented.
        const layout = "Jan 2, 2006 at 3:04pm (MST)"
        t := time.Date(2009, time.November, 10, 15, 0, 0, 0, time.Local)
        fmt.Println(t.Format(layout))
        fmt.Println(t.UTC().Format(layout))
        // Output:
    // Nov 10, 2009 at 3:00pm (PST)
        // Nov 10, 2009 at 11:00pm (UTC)
    }

Option 1: Go standard library

t.Format("20060102150405")

Unit	Golang Layout	Examples	Note
Year	06	21, 81, 01
Year	2006	2021, 1981, 0001
Month	January	January, February, December
Month	Jan	Jan, Feb, Dec
Month	1	1, 2, 12
Month	01	01, 02, 12
Day	Monday	Monday, Wednesday, Sunday
Day	Mon	Mon, Wed, Sun
Day	2	1, 2, 11, 31
Day	02	01, 02, 11, 31	zero padded day of the month
Day	_2	⎵1, ⎵2, 11, 31	space padded day of the month
Day	002	001, 002, 011, 031, 145, 365, 366	zero padded day of the year
Day	__2	⎵⎵1, ⎵⎵2, ⎵11, ⎵31, 365, 366	space padded day of the year
Part of day	PM	AM, PM
Part of day	pm	am, pm
Hour 24h	15	00, 01, 12, 23
Hour 12h	3	1, 2, 12
Hour 12h	03	01, 02, 12
Minute	4	0, 4 ,10, 35
Minute	04	00, 04 ,10, 35
Second	5	0, 5, 25
Second	05	00, 05, 25
10-1 to 10-9 s	.0 .000000000	.1, .199000000	Trailing zeros included
10-1 to 10-9 s	.9 .999999999	.1, .199	Trailing zeros omitted
Time zone	MST	UTC, MST, CET
Time zone	Z07	Z, +08, -05	Z is for UTC
Time zone	Z0700	Z, +0800, -0500	Z is for UTC
Time zone	Z070000	Z, +080000, -050000	Z is for UTC
Time zone	Z07:00	Z, +08:00, -05:00	Z is for UTC
Time zone	Z07:00:00	Z, +08:00:00, -05:00:00	Z is for UTC
Time zone	-07	+00, +08, -05
Time zone	-0700	+0000, +0800, -0500
Time zone	-070000	+000000, +080000, -050000
Time zone	-07:00	+00:00, +08:00, -05:00
Time zone	-07:00:00	+00:00:00, +08:00:00, -05:00:00

In Golang 1.17+ for fraction of seconds (.999 or .000) you can use , instead of . (,999 or ,000) but output is always with .!!! See https://github.com/golang/go/issues/48037

Option 2: strftime Go implementation

import strftime "github.com/itchyny/timefmt-go"

strftime.Format(t, "%Y%m%d%H%M%S")

See for more info

https://github.com/itchyny/timefmt-go

https://linux.die.net/man/3/strftime