Join an array with a block natively

Question

Is there a native way to join all elements of an array into a unique element like so:

[
  {a: "a"},
  {b: "b"}
].join do | x, y |
  x.merge(y)
end

To output something like:

{
  a: "a",
  b: "b"
}

The fact that I used hashes into my array is an example, I could say:

[
  0,
  1,
  2,
  3
].join do | x, y |
  x + y
end

Ends up with 6 as a value.

Answer 1

Enumerable#inject covers both of these cases:

a = [{a: "a"}, {b: "b"}]
a.inject(:merge) #=> {:a=>"a", :b=>"b"}
b = [0, 1, 2, 3]
b.inject(:+) #=> 6

inject "sums" an array using the provided method. In the first case, the "addition" of the sum and the current element is done by merging, and in the second case, through addition.

If the array is empty, inject returns nil. To make it return something else, specify an initial value (thanks @Hellfar):

[].inject(0, :+) #=> 0

Answer 2

[
  {a: "a"},
  {b: "b"}
].inject({}){|sum, e| sum.merge e}