Why doesn't the ruby ​​algorithm work?

Question

ruby

There is an array

arr = [
{key: 1, value: some_value441},
{key: 2, value: some_value212},
{key: 3, value: some_value33},
{key: 4, value: some_value44},
]

there is an algorithm that translates it into a hash.

arr.inject({}) do |previous, current|
  previous.merge({current[:id] => current[:title]})
end

It works and everything is fine, but I noticed if you add current to the end of the algorithm, it starts to output only one value, who can explain why this happens, or what should I read to understand it?

arr.inject({}) do |previous, current|
  previous.merge({current[:id] => current[:title]})
  current
end

Answer 1

To understand this, you need to read a book about ruby.
Ifcho - it says that every expression returns a value, and the body of the code block returns the value of the last expression, and the last expression you have is current.
Yes, you need to read the book.