&:

&:

The ampersand-colon combo turns out to be quite useful in saving keystrokes. What I had been doing was creating a new array of numbers. To do so quickly, I needed to use %w, which makes an array of strings.

ary = %w(23 45 68 120 345 760 1220)

The old way I converted to a number was the following:

ary.map! { |x| x.to_i }

(Naturally, I prefer map over collect, which does the same thing, not just because of the keystroke, but because I used Scheme before.) I discovered a shorter way:

ary.map!(&:to_i)

Actually, instead of doing it separately, why not combine the whole thing?

ary = %w(23 45 68 120 345 760 1220).map(&:to_i)

It saves using exclamation point and feels less dangerous.

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