CODEWITHSUNDEEP
go
user342673
user342673

Reputation: 674

convert YYYYMMDD string to a valid date in Go

I want to convert a string "20101011" to a valid date (2010-10-11), but could not figure our how to do it.

I tried:

now := time.Now()
date := now.Format("20101011")

and

date, _ := time.Parse("20101011", "20101011")

neither one worked.

Upvotes: 6

Views: 20756

Answers (3)

alkalinity
alkalinity

Reputation: 2030

If you don't mind another library, Google's civil package has a nice ParseDate() which skips the interim time.Time conversion. It can be used like so:

func ParseDate(s string) (Date, error) {
    date, err := civil.ParseDate(s)
    return Date{date}, err
}

Upvotes: 1

Angel Motta
Angel Motta

Reputation: 43

You can do the following:

dateStr := "20210131"                           // date in 'String' data type
dateValue, _ := time.Parse("20060102", dateStr) // convert 'String' to 'Time' data type
fmt.Println(dateValue)                          // output: 2021-01-31 00:00:00 +0000 UTC
dateStr = dateValue.Format("2006-01-02")       // Format return a 'string' in your specified layout (YYYY-MM-DD)
fmt.Println(dateStr)                           // Output: 2021-01-31

Upvotes: 1

peterSO
peterSO

Reputation: 166569

Package time

import "time"

Constants

const (
        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" // RFC822 with numeric zone
        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" // RFC1123 with numeric zone
        RFC3339     = "2006-01-02T15:04:05Z07:00"
        RFC3339Nano = "2006-01-02T15:04:05.999999999Z07:00"
        Kitchen     = "3:04PM"
        // Handy time stamps.
        Stamp      = "Jan _2 15:04:05"
        StampMilli = "Jan _2 15:04:05.000"
        StampMicro = "Jan _2 15:04:05.000000"
        StampNano  = "Jan _2 15:04:05.000000000"
)

These are predefined layouts for use in Time.Format and Time.Parse. The reference time used in the layouts is the specific time:

Mon Jan 2 15:04:05 MST 2006

which is Unix time 1136239445. Since MST is GMT-0700, the reference time can be thought of as

01/02 03:04:05PM '06 -0700

To define your own format, write down what the reference time would look like formatted your way; see the values of constants like ANSIC, StampMicro or Kitchen for examples. The model is to demonstrate what the reference time looks like so that the Format and Parse methods can apply the same transformation to a general time value.

Use the time format string "20060102" for YYYYMMDD. Use the time format string "2006-01-02" for YYYY-MM-DD.

For example,

package main

import (
    "fmt"
    "time"
)

func main() {
    now := time.Now()
    fmt.Println(now)
    date := now.Format("20060102")
    fmt.Println(date)
    date = now.Format("2006-01-02")
    fmt.Println(date)
    date2, err := time.Parse("20060102", "20101011")
    if err == nil {
        fmt.Println(date2)
    }
}

Output:

2009-11-10 23:00:00 +0000 UTC
20091110
2009-11-10
2010-10-11 00:00:00 +0000 UTC

Upvotes: 13

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