解析UTC日期字符串并转换为其他格式

Question

Go newcomer here.

I have a date string 2018-06-07T16:16:57Z and I want to convert it to something like this mm/dd/yyyy hh:mm.

This seems to be a frequently asked question, but I can't seem to find any previous questions that work for me.

I'm reading in a time field and trying to convert like this

time := row["Date & Time"]
fmt.Println(time)
t, _ := time.Parse("2006-01-02 15:04:05 -0700 UTC", time)
fmt.Println(t)

But I think the issue is that I don't have a correct format string. I've tried a few resources to no success.

When I print t as is, I get 0001-01-01 00:00:00 +0000 UTC as a result, which is obviously incorrect.

What I'd like to do is convert the time I'm reading in like this

newTime := currentDate.Format("01/02/2006 hh:mm")

Answer 1

You have two issues.

First, you should not name the variable time as that is the name of a built-in package. I suppose you knew that and this is just a copy paste error.

Next, the string you pass to time.Parse() is a format string that should describe the format of the time string from your database. You already know what the format is: 2018-06-07T16:16:57Z, so just use that replacing the value with Go's reference time.

Here is working variant:

package main

import (
    "fmt"
    "time"
)

func main() {
    tm := "2018-06-07T16:16:57Z"
    fmt.Println(tm)
    t, err := time.Parse("2006-01-02T15:04:05Z", tm)
    if err != nil {
        panic(err)
    }
    fmt.Println(t)
}

Run in playground

---

What's more the time format database uses is often described as RFC3339, which is also available as the time.RFC3339 constant in Go.

So using that simplifies your code even further:

package main

import (
    "fmt"
    "time"
)

func main() {
    tm := "2018-06-07T16:16:57Z"
    fmt.Println(tm)
    t, err := time.Parse(time.RFC3339, tm)
    if err != nil {
        panic(err)
    }
    fmt.Println(t)
}

Run in playground

---

And if you prefer, you could also let the database driver convert the time for you by scanning it to a time.Time variable.

For example:

var tm time.Time
if err = row.Scan(&tm); err != nil {
    panic(err)
}
fmt.Print(tm)