When parsing CSV file I need to combine fields of a row into an array starting from 4th field (3rd array element). I want to manipulate each row as in example below: Original array:
array1 = [1,2,3,4,5]
Changed array:
array2 = [1,2,3,[4,5]]
My code is here:
array1[0..2].push(array1[3..array1.length])
=> [1, 2, 3, [4, 5]]
My question is: Is there a better/cleaner/simpler way to convert part of an array into subarray?
There is! You can do this
a = a[0..2] + [a[3..-1]]. In ruby + can be used to concatenate arrays. Additionally, n..-1 gives you elements n to the end of the array. As a caveat, + is slower and more expensive than concat so if you were to do a[0..2].concat([a[3..-1]) it will be cheaper and faster.
["1", "2", "3", [4, 5]] - convert String to Integer for subarray. Utilizing your suggestion my code looks like this:a = ["1","2","3","4","5"] a = a[0..2].concat([a[3..-1].map(&:to_i)]) can this be improved? Sorry, I do's seem to be able to edit this comment
a[0..2] << a[3..-1].a = ["1","2","3","4","5"] a = a[0..2].concat([a[3..-1].map(&:to_i)]) there seem to always be another way in Ruby.
a + b creates a new array so three arrays have memory allocated whereas a.concat(b) concatenates b to a so only two arrays have memory allocated. Faster means that it runs more quickly.