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goals do
goal "Be able to use the basic building blocks of Ruby code"
goal "Use IRB to run Ruby code"
goal "Do simple calculations"
goal "Use and understand variables"
goal "Use and understand arrays"
goal "Use loops and conditional statements"
end
steps do
step do
message "Type this in the terminal to start the Interactive Ruby Shell, a program which lets you try out Ruby code:"
console_without_message "irb"
message "Yours might look different, but it should look something like this:"
irb_without_message(
"irb(main):001:0> "
)
end
step do
message "Next try some simple math that's built into Ruby. Type these lines into IRB:"
irb_without_message <<-RUBY
3 + 3
7 * 6
RUBY
end
step do
irb_with_message(
"**Variables** are names with values assigned to them.",
"my_variable = 5"
)
message "This assigns the value `5` to the name `my_variable`."
end
step do
irb_with_message(
"You can also do math with variables:",
<<-RUBY
my_variable + 2
my_variable * 3
RUBY
)
end
step do
message "Variables can also hold more than one value. This is called an **array**."
irb_without_message <<-RUBY
fruits = ["kiwi", "strawberry", "plum"]
RUBY
message "Here we're using the variable `fruits` to hold a collection of fruit names."
end
step do
irb_without_message <<-RUBY
fruits = fruits + ["orange"]
fruits = fruits - ["kiwi"]
RUBY
message "`+` and `-` are called operators. We can use them with the array of fruits just like we can use them with numbers."
end
step do
irb_with_message(
"Everything in Ruby has a **class**. Type this into IRB:",
<<-RUBY
7.class
"kiwi".class
fruits.class
RUBY
)
message "These are the three data types introduced so far: **Fixnum** (numbers), **String** (text), and **Array** (lists)."
end
step do
message <<-MARKDOWN
Each class has different **methods** that can be used on **instances**
of that class. If you're not quite sure what an instance is, [this page
on Ruby classes](http://docs.railsbridgeboston.org/ruby/classes) might
help
MARKDOWN
irb_without_message <<-RUBY
fruits.length
fruits.first
RUBY
message "You can see all the methods available for an object:"
irb_without_message <<-RUBY
fruits.methods
RUBY
irb_with_message(
"And you can call multiple methods in a row:",
<<-RUBY
fruits.methods.sort
RUBY
)
message <<-MARKDOWN
In `fruit.methods.sort` above, `fruit.methods` returns an array, and
`.sort` sorts that array. It's exactly like this, but without the `array`
variable:
MARKDOWN
irb_without_message <<-RUBY
array = fruits.methods
array.sort
RUBY
end
step do
message "Arrays have a method called **each** which iterates through the list running code on each item."
irb_without_message <<-RUBY
fruits.each do |fruit|
puts fruit
end
RUBY
message <<-MARKDOWN
This takes the first item from the `fruits` array (`"strawberry"`),
assigns it to the variable `fruit`, and runs the code between `do` and
`end`. Then it does the same thing for each other item in the list. The
code above should print a list of the fruits.
MARKDOWN
end
step do
message "A **conditional** runs code only when a statement evaluates to true."
irb_without_message <<-RUBY
if my_variable > 1
puts "YAY!"
end
RUBY
message "This prints `YAY!` if the value stored in `my_variable` is greater than 1."
message "Try changing the `>` in the conditional to a `<`."
end
step do
message "You can also make your own methods:"
irb_without_message <<-RUBY
def pluralize(word)
word + "s"
end
pluralize("kiwi")
RUBY
message "Methods take **parameters**, which are the variables they work on. In this case, we made a method called pluralize that takes one parameter, a word."
message "Methods can also return data. In this case, pluralize returns the word with an 's' added to the end of it. In Ruby, methods return whatever the last line of the method evaluates to."
end
step do
message "This is an *optional* practice question if you want to brush up on your Ruby. Feel free to skip it! Or talk to your TA if you get stuck, or discuss your solution once you have completed the checkpoint."
message "Write some Ruby that prints out the names of the people in your group."
message <<-MARKDOWN
Hints:
1. Start by opening up `irb`.
1. Create the names as strings in an array.
1. Store that array to a variable.
1. Then use the `.each` method on the stored array to loop through each of the names.
1. Use the `puts` method to print out the names.
MARKDOWN
end
end
next_step "creating_a_rails_application"
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