# Weekly Challenge

Solve the challenge, share your solution and summit the ranks of our Community!
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## Challenge #87: Losing Daylight

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Meteor

The first time I did it I used a reflexive join - it's much better with the Multi-Row Formula Tool! I'm glad the challenge helped me learn something new.

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Atom

i think this works..

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Alteryx Certified Partner

It's been awhile, what with work getting in the way.

Right, this is probably exactly the same as other solutions but here goes:

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I first used the date parser to convert the sunrise and sunset times. I then used a datetimediff() to determine the length of the day. I then used a multi-row formula to determine the difference in day length from one day to the next, used a separate stream into a summary tool to determine the overall total of minutes different and unioned the streams. Fairly straightforward:

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Atom

Here goes to the first challenge :-) and hopefully many more to come

-->Updated file has the sum of difference, which was missing from the first  :)

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Nebula

Working my way backwards in time ...

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Alteryx Certified Partner

Took me quite some time to figure out the proper syntax for the AM/PM identifier, as I did all the formatting in the formula tool.

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Asteroid

My solution is not as elegant as the majority that are here, however it should be dynamic enough to work fine with the next months data :) specifically changing the September Total to October Total.

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Alteryx Certified Partner

A nice one to get the brain working, I wanted the datetime tool to be more flexible in accepting am|pm and outputting as 24hr...sadly it was not therefore more work for me!  @Ned can this be a thing?

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Alteryx Certified Partner

Not sure if this is relevant, but there's a conversion for a 24 hour clock format which is datetimeformat(<field>,"%H"). This should give you 00 to 23 hours.

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Atom
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I converted everything to Alteryx Date format, so that we can also explore the result set in other tools (e.g. Tableau)