Some Methods in Ruby

Let us explore some methods in Ruby. So far we had seen a method like puts that writes to the screen. How does one accept user input? For this gets and chomp are useful. The example (Methods.rb) below illustrates the same.

# gets and chomp
puts "In which city do you stay?"
STDOUT.flush
city = gets.chomp
puts "The city is " + city

chomp is a string method and gets retrieves only strings from your keyboard. You must have realised that gets returns a string and a '\n' character, while chomp removes this '\n'.

There are many methods in the String class (you don't have to memorize them all; you can look up the documentation) like the reverse that gives a backwards version of a string (reverse does not change the original string). length that tells us the number of characters (including spaces) in the string. upcase changes every lowercase letter to uppercase, and downcase changes every uppercase letter to lowercase. swapcase switches the case of every letter in the string, and finally, capitalize is just like downcase, except that it switches the first character to uppercase (if it is a letter).

More on methods: If objects (such as strings, integers and floats) are the nouns in Ruby language, then methods are the verbs. Every method needs an object. It's usually easy to tell which object is performing the method: it's what comes right before the dot. Sometimes, though, it's not quite as obvious. When we are using puts, gets - where are their objects? In Ruby, the implicit object is whatever object you happen to be in. But we don't even know how to be in an object yet; we've always been inside a special object Ruby has created for us that represents the whole program. You can see always see what object you are in by using the special variable self.

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