[XorNot]

I had no idea what you were trying to do in the first paragraph whereas without knowing much ruby I can easily read the intent of the second.

[sheepmullet]

That has more to do with familiarity than anything else.

A tale of two cities is an easier book for an English speaker than Les Aventures de Tintin.

Map applies a function to each item in a collection.

As pseudo-code:

Collection.map(function)

And in the parents example we have:

[1,2,3].map(&:to_s)

The only Ruby specific part is &:.