Ruby/Arrays Hashes Ranges2

The first elements of the array:

toppings.first

The last element of the array:

toppings.last

To check if a data structure is an array:

puts toppings.type

or even better, use the class method since "type" is considered deprecated and will give you a warning.

puts toppings.class

An array does not have to include only data of a single type.You can can mix chars,strings or numbers as you please. Like this:

cool = ['i', 'see', 'u','!', 10]

As arrays, Hashes are used for storing data also.Hashes map an object to another object, think of assigning a string a certain "meaning" in your program; and each time you refer that string, you actually refer to it's meaning.

How to create an empty hash:

same as when creating an empty array: using the "new" method:

pizza = Hash.new

Or by using the curly brackets:

pizza = {
'marguerita' => 'tomato sauce and cheese',
'quattro formaggi' => 'mozzarella,gorgonzola,parmigiano and ricotta',
'quattro stagioni' => 'prosciutto, mozzarella, parmigiano,mushrooms,clams'
}

This is how you find out to what each "key" in the hash is associated with:

pizza['marguerita']