Ruby Tricks

Remove All but Word Characters from String

s.gsub(/\W+/,'')

Lowercase:

s.gsub(/\W+/,'').downcase

One-Liners

Factorial one-liner:

ruby -e "def fac(n) if n<=1 then 1 else fac(n-1)*n end end ; puts fac(10)"

Shorter and uglier factorial:

ruby -e "def f(n)n<2?1:f(n-1)*n end;puts f(10)"