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How to do date/time comparison

Submitted by: @import:stackoverflow-api··
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timedatehowcomparison

Problem

Is there any options in doing date comparison in Go? I have to sort data based on date and time - independently. So I might allow an object that occurs within a range of dates so long as it also occurs within a range of times. In this model, I could not simply just select the oldest date, youngest time/latest date, latest time and Unix() seconds compare them. I'd really appreciate any suggestions.

Ultimately, I wrote a time parsing string compare module to check if a time is within a range. However, this is not faring to well; I've got some gaping issues. I'll post that here just for fun, but I'm hoping there's a better way to time compare.

package main

import (
    "strconv"
    "strings"
)

func tryIndex(arr []string, index int, def string) string {
    if index  b and a is the lower limit
            return false
        }
    }
    return false
}

func timeGreaterEqual(a, b int) (bool, bool) {return a > b, a  b}

/*
 * Returns true for two strings formmated "hh:mm:ss".
 * Note: strings can actually be formatted like "h", "hh", "hh:m",
 * "hh:mm", etc. Any missing parts will be added lazily.
 */
func withinTime(timeRange, time string) bool {
    rArr := strings.Split(timeRange, "-")
    if timeCompare(rArr[0], rArr[1], timeLesserEqual) {
        afterStart := timeCompare(rArr[0], time, timeLesserEqual)
        beforeEnd := timeCompare(rArr[1], time, timeGreaterEqual)
        return afterStart && beforeEnd
    }
    // Catch things like `timeRange := "22:00:00-04:59:59"` which will happen
    // with UTC conversions from local time.
    // THIS IS THE BROKEN PART I BELIEVE
    afterStart := timeCompare(rArr[0], time, timeLesserEqual)
    beforeEnd := timeCompare(rArr[1], time, timeGreaterEqual)
    return afterStart || beforeEnd
}


So TLDR, I wrote a withinTimeRange(range, time) function but it's not working totally correctly. (In fact, mostly just the second case, where a time range crosses over days is broken. The original part worked, I just realized

Solution

Use the time package to work with time information in Go.


Time instants can be compared using the Before, After, and Equal
methods. The Sub method subtracts two instants, producing a Duration.
The Add method adds a Time and a Duration, producing a Time.

Play example:

package main

import (
    "fmt"
    "time"
)

func inTimeSpan(start, end, check time.Time) bool {
    return check.After(start) && check.Before(end)
}

func main() {
    start, _ := time.Parse(time.RFC822, "01 Jan 15 10:00 UTC")
    end, _ := time.Parse(time.RFC822, "01 Jan 16 10:00 UTC")

    in, _ := time.Parse(time.RFC822, "01 Jan 15 20:00 UTC")
    out, _ := time.Parse(time.RFC822, "01 Jan 17 10:00 UTC")

    if inTimeSpan(start, end, in) {
        fmt.Println(in, "is between", start, "and", end, ".")
    }

    if !inTimeSpan(start, end, out) {
        fmt.Println(out, "is not between", start, "and", end, ".")
    }
}

Code Snippets

package main

import (
    "fmt"
    "time"
)

func inTimeSpan(start, end, check time.Time) bool {
    return check.After(start) && check.Before(end)
}

func main() {
    start, _ := time.Parse(time.RFC822, "01 Jan 15 10:00 UTC")
    end, _ := time.Parse(time.RFC822, "01 Jan 16 10:00 UTC")

    in, _ := time.Parse(time.RFC822, "01 Jan 15 20:00 UTC")
    out, _ := time.Parse(time.RFC822, "01 Jan 17 10:00 UTC")

    if inTimeSpan(start, end, in) {
        fmt.Println(in, "is between", start, "and", end, ".")
    }

    if !inTimeSpan(start, end, out) {
        fmt.Println(out, "is not between", start, "and", end, ".")
    }
}

Context

Stack Overflow Q#20924303, score: 155

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