Feature #8970
openArray.zip and Array.product
Description
=begin
Most of the time when I use Array#zip
or Array#product
, I feel cumbursome that I have to take out the first array and pass it as a receiver. For example, if I have
a = [[:a, :b, :c], [:d, :e, :f], [:g, :h, :i]]
I have to do something like this:
a.first.zip(*a.drop(1)){...}
a.first.product(*a.drop(1)){...}
Sometimes, the receiver (i.e., the first array) has significance, but most other times, that breaks asymmetry, making the code look ugly.
I would be happy if we had Array.zip
and Array.product
in addition so that we can do it like this:
Array.zip(*a){...}
Array.product(*a){...}
=end
Updated by akr (Akira Tanaka) about 11 years ago
2013/10/1 sawa (Tsuyoshi Sawada) sawadatsuyoshi@gmail.com:
Feature #8970: Array.zip and Array.product
https://bugs.ruby-lang.org/issues/8970
Most of the time when I use
Array#zip
orArray#product
, I feel cumbursome that I have to take out the first array and pass it as a receiver. For example, if I havea = [[:a, :b, :c], [:d, :e, :f], [:g, :h, :i]]
I have to do something like this:
a.first.zip(*a.drop(1)){...} a.first.product(*a.drop(1)){...}
Sometimes, the receiver (i.e., the first array) has significance, but most other times, that breaks asymmetry, making the code look ugly.
I would be happy if we had
Array.zip
andArray.product
in addition so that we can do it like this:Array.zip(*a){...} Array.product(*a){...}
How different with Array#transpose ?
% ruby -e '
a = [[:a, :b, :c], [:d, :e, :f], [:g, :h, :i]]
p a.first.zip(*a.drop(1))
p a.transpose
'
[[:a, :d, :g], [:b, :e, :h], [:c, :f, :i]]
[[:a, :d, :g], [:b, :e, :h], [:c, :f, :i]]
Tanaka Akira
Updated by sawa (Tsuyoshi Sawada) about 11 years ago
akr, The difference between Array#transpose
and Array.zip
is just the same as with Array#transpose
and Array#zip
. That is, when any non-first array is shorter than the first, it is complemented with nil
.
Updated by sowieso (So Wieso) over 10 years ago
+1
This would make code more readable by not breaking the symmetry.
Also would be nice if the block version wouldn't return nil, but instead the concatenation of all return values, like map does. (not that an explicit map would hurt, but this is a waste of a return value)
Array.zip([1,2,3],[4,5,6]){|left,right| left + right} => [5,7,9]
Updated by marcandre (Marc-Andre Lafortune) over 10 years ago
This is a duplicate of https://bugs.ruby-lang.org/issues/6499 and https://bugs.ruby-lang.org/issues/7444.
Updated by marcandre (Marc-Andre Lafortune) over 10 years ago
- Has duplicate Feature #6499: Array::zip added
Updated by marcandre (Marc-Andre Lafortune) over 10 years ago
- Is duplicate of Feature #7444: Array#product_set added
Updated by osyo (manga osyo) about 5 years ago
If you use https://bugs.ruby-lang.org/issues/15955, you can write as follows.
class UnboundMethod
# apply or other name
def apply(receiver, *args)
bind(receiver).call(*args)
end
end
arrays = [["a", "b"], ["c"], ["d", "e"]]
p Array.instance_method(:product).apply(*arrays)
# => [["a", "c", "d"], ["a", "c", "e"], ["b", "c", "d"], ["b", "c", "e"]]
p Array.instance_method(:zip).apply(*arrays)
# => [["a", "c", "d"], ["b", nil, "e"]]
Need a syntax to call instance_method
like .:
?
Updated by sawa (Tsuyoshi Sawada) about 5 years ago
osyo (manga osyo) wrote:
If you use https://bugs.ruby-lang.org/issues/15955, you can write as follows.
class UnboundMethod # apply or other name def apply(receiver, *args) bind(receiver).call(*args) end end arrays = [["a", "b"], ["c"], ["d", "e"]] p Array.instance_method(:product).apply(*arrays) # => [["a", "c", "d"], ["a", "c", "e"], ["b", "c", "d"], ["b", "c", "e"]] p Array.instance_method(:zip).apply(*arrays) # => [["a", "c", "d"], ["b", nil, "e"]]
Need a syntax to call
instance_method
like.:
?
Thank you for the suggestion, but that looks a little too long. It can also be written as:
:product.to_proc.(*arrays)
# => [["a", "c", "d"], ["a", "c", "e"], ["b", "c", "d"], ["b", "c", "e"]]
:zip.to_proc.(*arrays)
# => [["a", "c", "d"], ["b", nil, "e"]]
But the proposal here seems to be favored more at least by mame-san (#16102).
Updated by duerst (Martin Dürst) almost 2 years ago
- Related to Feature #19324: Enumerator.product => Enumerable#product added