Ruby array each_slice_with_index?

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野趣味
野趣味 2021-02-01 13:30

If I have arr = [1, 2, 3, 4] I know I can do the following...

> arr.each_slice(2) { |a, b| puts \"#{a}, #{b}\" }
1, 2
3, 4

...A

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  • 2021-02-01 13:46
    arr.each_slice(2).with_index { |(*a), i| ...
    

    also note that the array, first parameter of the block, can be *arr

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  • 2021-02-01 13:50

    In 1.9 a lot of methods return an enumerator if no block is provided. You can call another method on the enumerator.

    arr = [1, 2, 3, 4, 5, 6, 7, 8] 
    arr.each_with_index.each_slice(2){|(a,i), (b,j)| puts "#{i} - #{a}, #{b}"}
    

    (Variation on @sepp2k). Result:

    0 - 1, 2
    2 - 3, 4
    4 - 5, 6
    6 - 7, 8
    
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  • 2021-02-01 14:06

    Like most iterator methods, each_slice returns an enumerable when called without a block since ruby 1.8.7+, which you can then call further enumerable methods on. So you can do:

    arr.each_slice(2).with_index { |(a, b), i| puts "#{i} - #{a}, #{b}" }
    
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