CODEWITHSUNDEEP
rubyarraysmultidimensional-array
Rahul
Rahul

Reputation: 1876

Slicing array of arrays

Sample array,

# sub-arrays are all of the same length
arr = [[1,2,3,4], [5,6,7,8], [2,4,6,8], [1,3,5,7]]

Now,

arr.some_slicing_technique(0..2)

should give me,

[[1,2,3], [5,6,7], [2,4,6], [1,3,5]]

Does some_slicing_technique exist? What would be the best way to solve this?

Upvotes: 2

Views: 139

Answers (3)

Victor Moroz
Victor Moroz

Reputation: 9225

A little more generic:

arr = [[1,2,3,4], [5,6,7,8], [2,4,6,8], [1,3,5,7]]
slice_lambda = lambda { |r| lambda{ |x| x[r]} }
arr.map(&slice_lambda[0..2])
# => [[1, 2, 3], [5, 6, 7], [2, 4, 6], [1, 3, 5]]
arr.map(&slice_lambda[1..2])
# => [[2, 3], [6, 7], [4, 6], [3, 5]]

Upvotes: 1

Sbhklr
Sbhklr

Reputation: 2703

You can do it like this:

[[1,2,3,4], [5,6,7,8], [2,4,6,8], [1,3,5,7]].map {|e| e.take(3)}

=> [[1, 2, 3], [5, 6, 7], [2, 4, 6], [1, 3, 5]]

Or if you want to use ranges:

[[1,2,3,4], [5,6,7,8], [2,4,6,8], [1,3,5,7]].map {|e| e[0..2]}

Upvotes: 8

sborsje
sborsje

Reputation: 601

You could transpose the original array, remove the last block and transpose it again:

arr.transpose[0..2].transpose

Upvotes: 5

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