# Using time (minutes, seconds) to calculate duration of events

**URL:** <https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624>\
**Category:** General Usage\
**Created:** [September 6, 2018, 2:25pm UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624 "2018-09-06T14:25:06Z")\
**Posts on this page:** 18\
**Page:** 1

<div class="post-metadata">

**Author:** ![Evian](https://avatars.discourse-cdn.com/v4/letter/e/5e9695/32.png) [@Evian](https://discourse.julialang.org/u/Evian)\
**Post date:** [September 6, 2018, 2:25pm UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/1 "2018-09-06T14:25:06Z")

</div>

I’ve read and tried the functionality included in Julia 1.0 for dates and times… I do not find an easy way - without defining functions or making manual calculations - of doing something simple as calculating the average pace when running a distance… In Excel is just one line of code… For example, if the total time is 32m45s, the pace is 32m45s /5 = 6m33s… How can this be done in Julia?

---

<div class="post-metadata">

**Author:** ![Sukera](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Sukera](https://discourse.julialang.org/u/Sukera)\
**Post date:** [September 6, 2018, 2:44pm UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/2 "2018-09-06T14:44:40Z")

</div>

What have you tried so far? Maybe have a look at [the docs](https://docs.julialang.org/en/v1/stdlib/Dates), especially the `Period` or the `Time` type (there do seem to be some missing arithmetic for durations though).

---

<div class="post-metadata">

**Author:** ![favba](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/favba/32/2735_2.png) [@favba](https://discourse.julialang.org/u/favba)\
**Post date:** [September 6, 2018, 2:51pm UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/3 "2018-09-06T14:51:46Z")

</div>

It seems `Dates` is intended for use for actual dates “management”. Division of an actual date is not something meaningful (for example, what is something `div( 09/06/2018 , 5)` supposed to mean?)  
For your actual usage I think you’d be better of with something like [Unitful.jl](http://ajkeller34.github.io/Unitful.jl/stable/) where just the unit “time” is defined.  
But it seems it is not updated to Julia v1.0 yet.

---

<div class="post-metadata">

**Author:** ![Sukera](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Sukera](https://discourse.julialang.org/u/Sukera)\
**Post date:** [September 6, 2018, 3:00pm UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/4 "2018-09-06T15:00:32Z")

</div>

Unitful is also a good idea, but you’re going to lose that separation between minutes and seconds - perhaps a new package for duration arithmetic would be good, since there doesn’t seem to be one? I’m thinking regular operations (\*, /, %, +, -, for a start?) with conversion between different overflow points (e.g. `50h 32m 22s` would be possible without overflowing, but `50h 70m 22s` would not be; that would overflow to `51h 10m 22s`). Doesn’t seem too complicated.

`Dates` does provide that mixed presentation to some degree, but breaks down when trying to add more seconds to this compund form:

```julia
julia> using Dates

julia> Minute(50)
50 minutes

julia> typeof(ans)
Minute

julia> Minute(50) + Minute(60)
110 minutes

julia> Minute(50) + Minute(60) + Second(30)
110 minutes, 30 seconds

julia> typeof(ans)
Dates.CompoundPeriod

julia> ans + Second(700)
ERROR: MethodError: no method matching +(::Type{Dates.CompoundPeriod}, ::Second)
Closest candidates are:
  +(::Any, ::Any, ::Any, ::Any...) at operators.jl:502
  +(::Dates.CompoundPeriod, ::Period) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.0/Dates/src/periods.jl:347
  +(::Time, ::TimePeriod) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.0/Dates/src/arithmetic.jl:82
  ...
Stacktrace:
 [1] top-level scope at none:0

```

Good catch on the distinction between a real Time and a Duration, @Evian!

---

<div class="post-metadata">

**Author:** ![favba](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/favba/32/2735_2.png) [@favba](https://discourse.julialang.org/u/favba)\
**Post date:** [September 6, 2018, 3:10pm UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/5 "2018-09-06T15:10:30Z")

</div>

Note that your `ans` variable is the `DataType` `Dates.CompoundPeriod`, that is why it is not working.

```julia
julia> using Dates

julia> Minute(50)
50 minutes

julia> typeof(ans)
Minute

julia> Minute(50) + Minute(60)
110 minutes

julia> t = Minute(50) + Minute(60) + Second(30)
110 minutes, 30 seconds

julia> t + Second(700)
110 minutes, 730 seconds 

```

What doesn’t work is division:

```julia
julia> t/5
ERROR: MethodError: no method matching /(::Dates.CompoundPeriod, ::Int64)
Closest candidates are:
  /(::Missing, ::Number) at missing.jl:93
  /(::BigInt, ::Union{Int16, Int32, Int64, Int8, UInt16, UInt32, UInt64, UInt8}) at gmp.jl:465
  /(::BigFloat, ::Union{Int16, Int32, Int64, Int8}) at mpfr.jl:380
  ...
Stacktrace:
 [1] top-level scope at none:0

```

On Julia v0.6.4 with `Unitful` you are able to do that:

```julia
julia> using Unitful

julia> (32u"minute" + 45u"s")/5
393//1 s

```

But the result will always be in seconds…

---

<div class="post-metadata">

**Author:** ![Sukera](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Sukera](https://discourse.julialang.org/u/Sukera)\
**Post date:** [September 6, 2018, 3:11pm UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/6 "2018-09-06T15:11:52Z")

</div>

Of course, thank you! 😅 It’s also not working for `*`.

Yes, that’s what I meant when I said you’d be losing the distinction between the fields - which is quite useful when talking about a Duration. That’s why I suggested maybe a new package would be a good idea for this 🙂

---

<div class="post-metadata">

**Author:** ![Tamas\_Papp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tamas_papp/32/25949_2.png) [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Post date:** [September 6, 2018, 3:42pm UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/7 "2018-09-06T15:42:20Z")

</div>

> [@Sukera](#):
>
> you’re going to lose that separation between minutes and seconds

I think that this is just a display/formatting issue. Work with seconds, display in `mm:ss`

---

<div class="post-metadata">

**Author:** ![Sukera](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Sukera](https://discourse.julialang.org/u/Sukera)\
**Post date:** [September 6, 2018, 4:18pm UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/8 "2018-09-06T16:18:48Z")

</div>

While true, fixing that display for just that specific use case using Unitful seems not that easy - and to do it without type piracy or overwriting some other display seems outright impossible to me (unless I’m missing something). At least when trying to support the custom final overflow field I described above.

---

<div class="post-metadata">

**Author:** ![Tamas\_Papp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tamas_papp/32/25949_2.png) [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Post date:** [September 6, 2018, 4:57pm UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/9 "2018-09-06T16:57:34Z")

</div>

> [@Sukera](#):
>
> to do it without type piracy or overwriting some other display seems outright impossible to me

If the only thing I need to fix is displaying the result, I would just use a wrapper type and define `Base.show` for it.

---

<div class="post-metadata">

**Author:** ![Evian](https://avatars.discourse-cdn.com/v4/letter/e/5e9695/32.png) [@Evian](https://discourse.julialang.org/u/Evian)\
**Post date:** [September 6, 2018, 10:20pm UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/10 "2018-09-06T22:20:58Z")

</div>

Thank you all of you for your answers and feedback. Here are my thoughts… You are the experts… As Date and Time are part of the Julia 1.0, I would extend the functionality for ‘duration’ in the next version, allowing for example operations. I would simplify the usage of period too by allowing its creation using a string. I would NOT create a separate package for it. If my memory still works, thats how other languages do.

---

<div class="post-metadata">

**Author:** ![KajWiik](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kajwiik/32/199_2.png) [@KajWiik](https://discourse.julialang.org/u/KajWiik)\
**Post date:** [September 7, 2018, 12:44am UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/11 "2018-09-07T00:44:26Z")

</div>

What about

```julia
julia> d1
2018-09-03T11:49:09

julia> d2
2018-09-03T11:45:33

julia> period = d1-d2
216000 milliseconds

julia> Dates.format(convert(DateTime, period), "MM:SS")
"03:36"

julia> speed = 300/(Dates.value(period)/1000)
1.3888888888888888

```

---

<div class="post-metadata">

**Author:** ![Tamas\_Papp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tamas_papp/32/25949_2.png) [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Post date:** [September 7, 2018, 5:48am UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/12 "2018-09-07T05:48:50Z")

</div>

> [@Evian](#):
>
> I would extend the functionality for ‘duration’ in the next version, allowing for example operations

`-` on `Date`, `Time`, etc already returns a specific type for the difference between the two, what are you proposing to do differently?

```julia
julia> using Dates

julia> d1 = Dates.now(); sleep(5); d2 = Dates.now()
d2 - d1
2018-09-07T07:46:47.7

julia> d2 - d1
5008 milliseconds

```

---

<div class="post-metadata">

**Author:** ![carstenbauer](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/carstenbauer/32/4981_2.png) [@carstenbauer](https://discourse.julialang.org/u/carstenbauer)\
**Post date:** [September 7, 2018, 7:42am UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/13 "2018-09-07T07:42:27Z")

</div>

@Tamas_Papp How would you convert these 5008 milliseconds to, say, seconds? AFAIK (correct me if I’m wrong) you have to use something like `Dates.value(d2-d1)/1000`. Arguably `(d2-d1)/1000` would be nicer. Or maybe `convert(Second, d)`.

---

<div class="post-metadata">

**Author:** ![Tamas\_Papp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tamas_papp/32/25949_2.png) [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Post date:** [September 7, 2018, 8:29am UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/14 "2018-09-07T08:29:10Z")

</div>

You cannot `convert(Second, Δ)` since you get an `InexactError` in general, but for display purposes (internal calculations within the `show` method)

```julia
divrem(Δ, Millisecond(1000))

```

and similar should work.

---

<div class="post-metadata">

**Author:** ![Evian](https://avatars.discourse-cdn.com/v4/letter/e/5e9695/32.png) [@Evian](https://discourse.julialang.org/u/Evian)\
**Post date:** [September 7, 2018, 11:12am UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/15 "2018-09-07T11:12:25Z")

</div>

This works as long you use time with its constrains, for example, number of hours less than 24…

---

<div class="post-metadata">

**Author:** ![Evian](https://avatars.discourse-cdn.com/v4/letter/e/5e9695/32.png) [@Evian](https://discourse.julialang.org/u/Evian)\
**Post date:** [September 7, 2018, 11:15am UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/16 "2018-09-07T11:15:22Z")

</div>

as mentioned before 1) it does not allow hours greater than 24 (time and period are two different things) and 2) the results is milliseconds and it needs to be converted into minutes and seconds. I would expect a simple operation like d1 = 72m12s ; d1/5 = 14m26s400ms

---

<div class="post-metadata">

**Author:** ![stephancb](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stephancb/32/14243_2.png) [@stephancb](https://discourse.julialang.org/u/stephancb)\
**Post date:** [September 7, 2018, 2:58pm UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/17 "2018-09-07T14:58:53Z")

</div>

You can do

```julia
julia> DateTime(0,1,1)+(Second(Minute(32))+Second(45))/5
0000-01-01T00:06:33

```

which is so far the shortest suggestion replicating the Excel example as closely as possible, I think.

It would be nicer not having to add a DateTime, to get a segmented period (days, hours, …).

---

<div class="post-metadata">

**Author:** ![stevengj](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stevengj/32/71_2.png) [@stevengj](https://discourse.julialang.org/u/stevengj)\
**Post date:** [September 7, 2018, 4:11pm UTC](https://discourse.julialang.org/t/using-time-minutes-seconds-to-calculate-duration-of-events/14624/18 "2018-09-07T16:11:47Z")

</div>

> [@stephancb](#):
>
> It would be nicer not having to add a DateTime, to get a segmented period (days, hours, …).

```julia
julia> canonicalize(Dates.CompoundPeriod((Second(Minute(32))+Second(45))/5))
6 minutes, 33 seconds

```