Ruby on rails: replace camel case with space

Question

I want to convert camel case words like camelCase to CAMEL CASE. I tried the approach mentioned here.

@q = params[:promo].underscore.humanize.upcase

But this gives me CAMELCASE and not CAMEL CASE same result on using:

@q = params[:promo].gsub(/[a-zA-Z](?=[A-Z])/, '\0 ').downcase

EDIT: the url contains /camelCase but on using params[:promo], the camel case is not retained and @q is camelcase

Answer 1

»  'camelCase'.underscore.humanize.upcase
=> "CAMEL CASE"

Answer 2

If anyone need something like 'CamelCase' to 'Camel Case' can use

'CamelCase'.underscore.split('_').collect{|c| c.capitalize}.join(' ')

Or 'CamelCase' to 'camel case'

'CamelCase'.underscore.split('_').join(' ') 

Or 'CamelCase' to 'Camel case'

'CamelCase'.underscore.humanize

N.B: This solution is rails specific, it does not work in ruby without ActiveSupport.