I'm learning the details of how each works in ruby, and I tried out the following line of code:
p [1,2,3,4,5].each { |element| el }
And the result is an array of
[1,2,3,4,5]
Why is the return value of each the same array? Doesn't each just provide a method for iterating? Or is it just common practice for the each method to return the original value?
Array#each returns the [array] object it was invoked upon: the result of the block is discarded. Thus if there are no icky side-effects to the original array then nothing will have changed.
Perhaps you mean to use map?
p [1,2,3,4,5].map { |i| i*i }
If you want, for some reason, to suppress the output (for example debugging in console) here is how you can achive that
[1,2,3,4,5].each do |nr|
puts nr.inspect
end;nil
end;nil IS WHAT I'VE BEEN SEARCHING FOR MY WHOLE LIFE!!!
end;nil is the same as just a return nil in the next line after end. The return can be omitted, as ruby methods always return the last statement.
The block form of Array#each returns the original Array object. You generally use #each when you want to do something with each element of an array inside the block. For example:
[1, 2, 3, 4, 5].each { |element| puts element }
This will print out each element, but returns the original array. You can verify this with:
array = [1, 2, 3, 4, 5]
array.each { |element| element }.object_id === array.object_id
=> true
If you want to return a new array, you want to use Array#map or one of its synonyms. The block form of #map returns a different Array object. For example:
array.object_id
=> 25659920
array.map { |element| element }.object_id
=> 20546920
array.map { |element| element }.object_id === array.object_id
=> false
You will generally want to use #map when you want to operate on a modified version of the original array, while leaving the original unchanged.
All methods return something. Even if it's just a nil object, it returns something.
It may as well return the original object rather than return nil.
each {|item| block } → aryso yeseach{block}method ofArrayclass returnsselfnil). As a bonus it allows you to chain methods to further operate on the array if you want.