> On Jan 31, 2017, at 12:46 PM, Ben Cohen via swift-evolution
> <[email protected]> wrote:
>
>> // apply alternating view background colors
>> for (i, view) in views.enumerated() {
>> view.backgroundColor = i % 2 ? bgColor1 : bgColor2
>> }
>>
>
> This is an interesting one because it highlights something else I think is
> missing from the std lib: Sequence.cycle, which would make an infinite
> sequence by repeating a sequence, enabling what I think is probably a
> readability win in some cases:
>
> let colors = [bgColor1, bgColor2].cycle
> for (color, view) in zip(colors, views) {
> view.backgroundColor = color
> }
This is a common enough need for me that I have built a special class for it.
Here is the code in case it is useful to others trying to do the same thing:
https://gist.github.com/jonhull/b9cd8a50abca16ea49eade2c91edf8a2
At it’s heart, it takes an array (or a single value) and turns it into an
endless repeating collection. It also has facilities for random output, and to
compose with other sources, allowing complex repeating patterns from simple
sources. I originally made it for creating fill patterns in a drawing
framework (e.g. stripes like your example above), but I have found it generally
useful over time.
Thanks,
Jon
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