Question

I am new to ruby , can someone explain what the second and 3rd line do?

a = [6,7,8]
a.send :[]=,0,2
a[0] + a.[](1) + a.send(:[],2)

First line is assigning an array to the variable a.

I am totally lost on second and third line. hope someone can give some detail explannations.

Thanks!!!

Answer 1

.send invokes the method identified by symbol, passing it any arguments specified.

a.send :[]=,0,2

is same as

a.send(:[]=, 0, 2)

Means invoke []= method on the array object with first parameter as 0 and second parameter as 2.

So this is a[0] = 2, set the first element of the array to 2.

After executed a.send :[]=,0,2, a becomes [2, 7, 8].

a.[](1) is same as a[1]

a.send(:[], 2) is same as a.[](2) which is a[2].

So a[0] + a.[](1) + a.send(:[],2) equals a[0] + a[1] + a[2] equals 2 +7 + 8 equals 17.