Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Update methods and return values md #42

Open
wants to merge 1 commit into
base: gh-pages
Choose a base branch
from
+6 −6
Open

Update methods and return values md #42

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 6 additions & 6 deletions module1/lessons/methods_and_return_values.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -147,7 +147,7 @@ pry(main)> "Hello World".gsub "World", "Turing"

## Variables

Variables are keywords that we create to hold or point to return values that we want to maintain and re-use. In the example above, if we want to re-use the return value `"hello world"`, instead of calling `"Hello World".downcase` over and over again, we can assign the return value to a `variabl` to be used at later points in our code.
Variables are keywords that we create to hold or point to return values that we want to maintain and re-use. In the example above, if we want to re-use the return value `"hello world"`, instead of calling `"Hello World".downcase` over and over again, we can assign the return value to a `variable` to be used at later points in our code.

```ruby
pry(main)> greeting = "Hello World".downcase
Expand All @@ -160,7 +160,7 @@ pry(main)> "This is our greeting: #{greeting}"
=> "This is our greeting: hello world"
```

Since *we* define variables, we can also reassign them. Once reassigned, the original return value is gone - it can not be recalled with that variable.
Since *we* define variables, we can also reassign them. Once reassigned, the original return value is gone - it cannot be recalled with that variable.

```ruby
pry(main)> greeting = "Hello World".downcase
Expand All @@ -185,9 +185,9 @@ pry(main)> greeting == "Hello World".downcase

## Defining our own Methods

`.upcase`, `.include?`, and `.gsub` are all **Methods** built in to the string class. What if we want to create our own class with its own methods?
`.upcase`, `.include?`, and `.gsub` are all **Methods** built into the string class. What if we want to create our own class with its own methods?

Let's make a class that calculators values. In a new file called `calculator.rb`, we'll add the following lines of code and run this file from the command line using `ruby calculator.rb`.
Let's make a class that calculates values. In a new file called `calculator.rb`, we'll add the following lines of code and run this file from the command line using `ruby calculator.rb`.

```ruby
class Calculator
Expand Down Expand Up @@ -383,7 +383,7 @@ puts calculator.add(1,3)

Following the directions in [this gist](https://gist.github.com/ameseee/c311860e9f6bc023036351f298907ccb), work with your partner through the activities.

You focus should be exploring to build a deep understanding of these concepts, NOT to race through the activity for the sake of finishing it. Whether you know this stuff or not, there should be plenty for you and your partner to talk about/dig into during this time.
Your focus should be exploring to build a deep understanding of these concepts, NOT to race through the activity for the sake of finishing it. Whether you know this stuff or not, there should be plenty for you and your partner to talk about/dig into during this time.

## Method Lookup

Expand Down Expand Up @@ -447,7 +447,7 @@ Think about how you drive a car. You don't need to know how a combustion engine

![](https://camo.githubusercontent.com/07f5ef4748c194ee893c18089a2b6513d473ac37/687474703a2f2f6d696e6573662e636f6d2f7265736f75726365732f6363612f77702d636f6e74656e742f75706c6f6164732f323031302f30312f61627374726163742d6f2d6d65746572312e6a7067)

If we look at our `calculator.rb` file, what we really want to do is take two numbers, print a welcome, and then print the sum of those two numbers. `print_sum` is a method that does exactly that. Bundling methods into more abstract methods can help us to create more complex programs. Tl;dr- Abstraction is an object-oriented programming concept that means that complexity is being hidden from the user.
If we look at our `calculator.rb` file, what we really want to do is take two numbers, print a welcome message, and then print the sum of those two numbers. `print_sum` is a method that does exactly that. Bundling methods into more abstract methods can help us to create more complex programs. Tl;dr- Abstraction is an object-oriented programming concept that means that complexity is being hidden from the user.


A note on order: The way you define the order of your _methods_ does not matter. The way you call them **does**. Ruby will **parse** each method in the class and then when a method is **called** Ruby will **execute** the parsed methods accordingly.
Expand Down