Scripts and Methods

Introduction

Let's start this section with a few definitions:

• script --> A file that contains code. We run ruby scripts from the terminal by typing:

    ruby script_name.rb
  

• method --> A function or set of commands that are bundled together. We can use scripts to define methods and execute them.

You've already used several methods. #capitalize and even + (integer addition) are ruby methods! We haven't written any scripts yet. Let's change that!

Our first script

• Create a new file called my_script.rb

• Enter the following code into that file:

  puts "hello, world!"
  

• Using the terminal, navigate to the directory containing my_script.rb

• Tell your computer to run the script by typing: ruby my_script.rb

  

Notice that we used the puts method to tell the computer to print the string to the terminal. Nothing is printed automatically from scripts (like it is in pry/irb). Instead, we have to tell the computer manually whenever we want it to print something.

Our First Method

Let's change our my_script.rb file to instead look like this:

  def say_hello
    puts "hello"
  end

In this file, we're now defining a method called #say_hello (the '#' in documentation is used to tell the reader that we're talking about a method). #say_hello is responsible for printing 'hello' to the screen.

Let's run our script.

Notice that nothing happens. Well, in our script, we defined a method, but we never invoked the method. Let's amend our script to also invoke #say_hello.

  def say_hello
    puts "hello"
  end

  say_hello

Let's run our script again.

Arguments

Arguments are pieces of information that we pass to methods. Let's re-write our script to instead define a method called #say_hello_to. This method should accept one argument, the name of the person to say hello to!

  def say_hello_to(name)
    puts "hello, " + name
  end

  say_hello_to("Chen")
  say_hello_to("Rosalie")
  say_hello_to("Ksenia")

Let's run our new script.

95% of JumpStart will be focused on defining methods

From this point on, you will be expected to create scripts, define methods, and run them.