I feel like i've seen this question somewhere before but i cannot find it and i'm pretty sure ruby has a one liner for looping over something and adding the items to an array:
items = []
some_stuff.each do |stuff|
items << stuff
end
items
4 Answers
this way?
items = some_stuff.inject([]) { |acc, item| acc + [item] }
obviously this exact snippet doesn't make sense because it's another array with the same value, you could just dup some_stuff, but I think can help you anyway
4 Comments
Rajagopalan
He is not asking for summation of the items, he is asking for adding into the array which he simply can assign it.
Ursus
I'm not adding anything. I do not mutate the object, that's all
Rajagopalan
Ah!!! sorry, I misunderstood you. Thanks for clarifying.
Stefan
Note that this creates two new arrays on each iteration: one for
[item] and one as the result of acc + [item].Is this what you are looking for?
some_stuff=[1,2,3,4,6,7]
Code
items=some_stuff.each_with_object([]){|value,items|items.push(value)}
p items
Output
[1, 2, 3, 4, 6, 7]
Comments
If some_stuff responds to each, then it very likely also conforms to the Enumerable protocol. (It would be silly not to, since each is all you need to support the Enumerable protocol via include Enumerable.)
The Enumerable protocol includes the method Enumerable#to_a, which returns the elements of the Enumerable as an Array:
to_a→arrayReturns an array containing the items in
self:(0..4).to_a # => [0, 1, 2, 3, 4]
So, assuming that some_stuff really does conform to the Enumerable protocol, all you need to do is
items = some_stuff.to_a
However, unless you absolutely need the specific features an Array provides, there is no need to even do this. If some_stuff really does conform to the Enumerable protocol, then most of the methods that you would use on the Array already exist on some_stuff as well, and they may even be more efficient because some_stuff knows more about what its internal structure is and what the structure of the elements is than Array does.
There is often no need to convert an Enumerable to an Array.
Comments
You could use splat operator if working with an array
items = [*some_stuff]
Enumerable#reduceorEnumerable#each_with_objectwould do the jobreduceis only for summation? Reduce is Ruby's answer tofoldHOF and it can do this job perfectly fine. Which one to pick is just a matter of personal preferences or conventionsitems = some_stuff.dupis all you need. Or maybeitems.concat(some_stuff)to append to an existing array.Enumerable#map, e.g.items = some_stuff.map { |stuff| stuff.whatever }? Your initial example is probably too simplified for what you actually intend to do.