如何获得时间戳之间的差异（字符串之间或time.time之间）

Question

This question already has an answer here:

• Parsing date string in Go 6 answers
• Difference between two time.Time objects 3 answers

I have one problem: I need to know the difference/duration between two timestamps in golang. Therefore, I use the time library (https://golang.org/pkg/time/).

If I have two timestamps of type "time.time", it is easy to get the difference using "time.Sub()". My problem is that one of my timestamps comes from another function and it is only possible to transfer it as a string:

t1 := "2009-11-10 23:00:00 +0000 UTC m=+0.000000001" //type: string

t2 := time.Now() //type: time.time

Now I have to basic possibilities:

A) Convert t2 to a string as well and try to find out the difference between two strings (UGLY)

B) Convert t1 from type "string" to type "time.time" and then apply "time.Sub()"

I want to go way B). Therefore, I found out that

time.Parse(format, timestring)

should be able to do so. So I tried to convert t1 using

t1_time, err := time.Parse(time.RFC3339, t1)

but the result was not as expected! Instead I got this

0001-01-01 00:00:00 +0000 UTC

and the error saying "error parsing time "2009-11-10 23:00:02 +0000 UTC m=+2.000000001" as "2006-01-02T15:04:05Z07:00": cannot parse " 23:00:02 +0000 UTC m=+2.000000001" as "T" ".

If I use my own timeformat which is the same as t1

timeformat := "2009-11-10 23:00:00 +0000 UTC m=+0.000000001"

t1_time, err := time.Parse(timeformat , t1)

the result stays wrong and I get the error saying"error parsing time "2009-11-10 23:00:02 +0000 UTC m=+2.000000001" as "2009-11-10 23:00:00 +0000 UTC m=+0.000000001": cannot parse "9-11-10 23:00:02 +0000 UTC m=+2.000000001" as "009-" ".

I also tried to go over UNIX time but the time library does not allow me to convert a string into unix.

What do I do wrong??! Why is the parsing not working? Thanks for any help!

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Answer 1

Basically you want:

    t1_raw := "2009-11-10 23:00:00 +0000 UTC m=+0.000000001"
    format := "2006-01-02 15:04:05 -0700 MST"

    // for simplicity t1_raw[:29] discards time's monotonic delta
    // i.e. the " m=+0.000000001" suffix

    t1, err := time.Parse(format, t1_raw[:29])
    if err != nil {
            log.Fatal(err)
    }

    log.Println("Duration ->", t2.Sub(t1))

If you really want the monotonic delta included, that number would have to be parsed manually and the delta applied to t1.

Playground version.

Note: playground version will show a duration of zero - as the playground's clock starts on Nov 11 2009 - the seminal birthdate of go.