Go by Example: Time Formatting / Parsing

Go supports time formatting and parsing via pattern-based layouts.

 
package main

import "fmt"
import "time"

func main() {
    p := fmt.Println

Here’s a basic example of formatting a time according to RFC3339.

 
    t := time.Now()
    p(t.Format("2006-01-02T15:04:05Z07:00"))

Format uses an example-based layout approach; it takes a formatted version of the reference time Mon Jan 2 15:04:05 MST 2006 to determine the general pattern with which to format the given time. Here are a few more examples of time formatting.

 
    p(t.Format("3:04PM"))
    p(t.Format("Mon Jan _2 15:04:05 2006"))
    p(t.Format("2006-01-02T15:04:05.999999-07:00"))

For purely numeric representations you can also use standard string formatting with the extracted components of the time value.

 
    fmt.Printf("%d-%02d-%02dT%02d:%02d:%02d-00:00\n",
        t.Year(), t.Month(), t.Day(),
        t.Hour(), t.Minute(), t.Second())

Time parsing uses the same example-based approach as Formating. These examples parse times rendered with some of the layouts used above.

 
    withNanos := "2006-01-02T15:04:05.999999999-07:00"
    t1, e := time.Parse(
        withNanos,
        "2012-11-01T22:08:41.117442+00:00")
    p(t1)
    kitchen := "3:04PM"
    t2, e := time.Parse(kitchen, "8:41PM")
    p(t2)

Parse will return an error on malformed input explaining the parsing problem.

 
    ansic := "Mon Jan _2 15:04:05 2006"
    _, e = time.Parse(ansic, "8:41PM")
    p(e)

There are several predefined formats that you can use for both formatting and parsing.

 
    p(t.Format(time.Kitchen))
}

$ go run time-formatting-parsing.go 
2012-11-02T09:35:03-07:00
9:35AM
Fri Nov  2 09:35:03 2012
2012-11-02T09:35:03.982519-07:00
2012-11-02T09:35:03-00:00
0001-01-01 00:00:00 +0000 UTC
0000-01-01 20:41:00 +0000 UTC
parsing time "8:41PM" as "Mon Jan _2 15:04:05 2006": ...
9:35AM

Next example: Random Numbers.

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