Added stablePartition by condition array method

[neoneye]

Checklist

• I checked the Contributing Guidelines before creating this request.
• New extensions are written in Swift 4.
• New extensions support iOS 8.0+ / tvOS 9.0+ / macOS 10.10+ / watchOS 2.0+.
• I have added tests for new extensions, and they passed.
• All extensions have a clear comments explaining their functionality, all parameters and return type in English.
• All extensions are declared as public.
• I have added a changelog entry describing my changes.

[neoneye]

This function is inspired by Ruby's partition function, http://ruby-doc.org/core-2.5.0/Enumerable.html#method-i-partition

The name partition is already taken by the Swift Array class. The second best name I could come up with is: stablePartition, since the element ordering is preserved.

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[codecov]

Codecov Report

Merging #367 into master will increase coverage by 0.04%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #367      +/-   ##
==========================================
+ Coverage   90.68%   90.73%   +0.04%     
==========================================
  Files          53       53              
  Lines        2470     2482      +12     
==========================================
+ Hits         2240     2252      +12     
  Misses        230      230

Flag	Coverage Δ
#ios	90.73% <100%> (+0.04%)	⬆️
#osx	86.98% <100%> (+0.06%)	⬆️
#tvos	86.98% <100%> (+0.06%)	⬆️

Impacted Files	Coverage Δ
...urces/Extensions/SwiftStdlib/ArrayExtensions.swift	100% <100%> (ø)	⬆️
...rces/Extensions/SwiftStdlib/StringExtensions.swift	99.37% <0%> (ø)	⬆️

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[LucianoPAlmeida]

Hey @neoneye, Thank you for your contribution :)
Great extension and implementation :)
Just suggestion about the naming, what you think about divided(by:)?
I'm not good at naming 😅 but I think divided(by:) makes sense in this context. What do you think? :)

[neoneye]

I'm not a native english speaker, so I don't know.

Your name divided(by:) is great.

Ideas for other names: separate, split, order.

[LucianoPAlmeida]

Looks good to me :)

[neoneye]

@LucianoPAlmeida I just added parameter names to the returned tuple. Perhaps this is helpful to some users. I can't think of more things. I think it's ready for merge.

[neoneye]

@LucianoPAlmeida wait a little. I'm considering moving it to the Collection extension.

[LucianoPAlmeida]

@neoneye Moving to collection is a good idea :)

Updated PR

[neoneye]

Olà @LucianoPAlmeida

The current Array.divided(by:) in ArrayExtension has simple and short tests, easy to understand. I think the PR as it is now, is good.

I have made a collection-dividedby branch. Here the Collection.divided(by:) has unfortunately complicated the tests. I doubt anyone will ever use it for splitting dictionaries/strings. I think Arrays is the primary usecase.

Perhaps you can decide if you want divided(by:) to be placed in the ArrayExtension or in the CollectionExtension ?

[LucianoPAlmeida]

@neoneye I agree that Array is the primary use case, so maybe it's enough to let it just as an Array extension :)

[SD10]

@neoneye @LucianoPAlmeida Thank you for this 💪 💯