Can you supply arguments to the map(&:method) syntax in Ruby?

Question

You\'re probably familiar with the following Ruby shorthand (a is an array):

a.map(&:method)

For example, try the followin

Answer 1

For your example can be done a.map(&2.method(:+)).

Arup-iMac:$ pry
[1] pry(main)> a = [1,3,5,7,9]
=> [1, 3, 5, 7, 9]
[2] pry(main)> a.map(&2.method(:+))
=> [3, 5, 7, 9, 11]
[3] pry(main)> 

Here is how it works :-

[3] pry(main)> 2.method(:+)
=> #
[4] pry(main)> 2.method(:+).to_proc
=> #
[5] pry(main)> 2.method(:+).to_proc.call(1)
=> 3

2.method(:+) gives a Method object. Then &, on 2.method(:+), actually a call #to_proc method, which is making it a Proc object. Then follow What do you call the &: operator in Ruby?.