ActiveSupport Inflections - humanize vs titleize

ActiveSupport has a lot of useful inflections to transform strings, and I often forget which one does what exactly.

#humanize will capitalize the first word, whereas #titleize will capitalize every word:

"hi_how_are_you?".humanize
# => "Hi how are you?"

"hi_how_are_you?".titleize
# => "Hi How Are You?"

Actually, it turns out #titleize is just a special case of #humanize!