# Time period conversion to seconds, for plotting

**URL:** <https://discourse.julialang.org/t/time-period-conversion-to-seconds-for-plotting/123422>\
**Category:** General Usage\
**Tags:** dates\
**Created:** [December 3, 2024, 5:12am UTC](https://discourse.julialang.org/t/time-period-conversion-to-seconds-for-plotting/123422 "2024-12-03T05:12:43Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![merlin](https://avatars.discourse-cdn.com/v4/letter/m/8baadc/32.png) [@merlin](https://discourse.julialang.org/u/merlin)\
**Post date:** [December 3, 2024, 5:12am UTC](https://discourse.julialang.org/t/time-period-conversion-to-seconds-for-plotting/123422/1 "2024-12-03T05:12:43Z")

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Meganecroposting here because of this problem I ran into while trying to format ticks on a logarithmic x-axis that represents time intervals.

```julia
using Dates

convert(Second, Week(100))
60480000 seconds

convert(Second, Month(3))
ERROR: MethodError: Cannot `convert` an object of type Month to an object of type Second

```

So much for compound periods and so forth.

The solution above will help me design a function to solve my problem, but also I’m looking into the Unitful.jl pacakge.

---

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**Author:** ![Dan](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/dan/32/42581_2.png) [@Dan](https://discourse.julialang.org/u/Dan)\
**Post date:** [December 3, 2024, 5:43am UTC](https://discourse.julialang.org/t/time-period-conversion-to-seconds-for-plotting/123422/2 "2024-12-03T05:43:33Z")

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> [@merlin](#):
>
> ```julia
> convert(Second, Month(3))
> 
> ```

As usual with Date/Time stuff things are complicated.  
A month does not have a constant number of seconds.  
So, error. Can’t think of a way to fix this. Perhaps return an interval of possible answers.

---

<div class="post-metadata">

**Author:** ![merlin](https://avatars.discourse-cdn.com/v4/letter/m/8baadc/32.png) [@merlin](https://discourse.julialang.org/u/merlin)\
**Post date:** [December 3, 2024, 5:07pm UTC](https://discourse.julialang.org/t/time-period-conversion-to-seconds-for-plotting/123422/3 "2024-12-03T17:07:07Z")

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Yes well good news! I read some docs, esp. the Unitful.jl docs by which I found out about the Dates FixedPeriod type. It makes sense, a month or year is not a fixed number of days/hours/sec etc.

```julia
help?> Dates.FixedPeriod

  Summary
  ≡≡≡≡≡≡≡

  Dates.FixedPeriod is of type Union.

  Union Composed of Types
  ≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡

    • Day

    • Hour

    • Microsecond

    • Millisecond

    • Minute

    • Nanosecond

    • Second

```

So Dates types wont convert to Month/Year because of the indeterminate length, depending on the specific date. Unitful defines a year as exactly 365.25 days though, so the conversion works for year but not months.

```julia
Using Unitful

uconvert(u"s", 1*u"yr")
31557600 s

```

Good design by the Julia Team! I’ll just create a function to display units the way I like.