Question

In the book I’m reading to learn Rails (RailsSpace) , the author creates two functions (below) to turn all caps city names like LOS ANGELES into Los Angeles. There’s something I don’t get about the first function, below, however.

Namely, where does “word” come from? I understand that “word” is a local/block variable that disappears after the function has been completed, but what is being passed into/assigned to “word.” IN other words, what is being split?

I would have expected there to have been some kind of argument taking an array or hash passed into this function…and then the “each” function run over that..

def capitalize_each
  space = " "
  split(space).each{ |word| word.capitalize! }.join(space)     
end   

# Capitalize each word in place.     
def capitalize_each!
  replace capitalize_each end
end

Answer 1

At first I thought that the method was incomplete because of the absence of self at the beginning but it seems that even without it split is being called over the string given, space would simply be a default separator. This is how the method could look with explicit self.

class String
    def capitalize_each(separator = ' ')
        self.split(separator).each{|word| word.capitalize!}.join(separator)
    end
end

puts "LOS ANGELES".capitalize_each #=> Los Angeles
puts "LOS_ANGELES".capitalize_each('_') #=> Los_Angeles