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I'm just learning Ruby so apologies if this is too newbie for around here, but I can't work this out from the pickaxe book (probably just not reading carefully enough). Anyway, if I have an array like so:
arr = [1,2,3,4,5] ...and I want to, say, multiply each value in the array by 3, I have worked out that doing the following:
arr.each {|item| item *= 3} ...will not get me what I want (and I understand why, I'm not modifying the array itself).
What I don't get is how to modify the original array from inside the code block after the iterator. I'm sure this is very easy.
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To directly modify the array, use arr. map! {|item| item*3} . To create a new array based on the original (which is often preferable), use arr.
Ruby | Array replace() function Array#replace() : replace() is a Array class method which returns an array of all combinations of elements from all arrays. Return: an array of all combinations of elements from all arrays.
The Ruby Enumerable#each method is the most simplistic and popular way to iterate individual items in an array. It accepts two arguments: the first being an enumerable list, and the second being a block. It takes each element in the provided list and executes the block, taking the current item as a parameter.
Use map to create a new array from the old one:
arr2 = arr.map {|item| item * 3} Use map! to modify the array in place:
arr.map! {|item| item * 3} See it working online: ideone
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