We're going to start working with Ruby! Ruby is a programming language and will be the foundation of most everything we learn for the next 6 months.
Like learning any new language, getting good at Ruby will just take practice. You'll find over time that there's nothing "magic" about programming - you're issuing commands that a computer understands and can execute.
Ruby is different than other programming languages. It was written with the human in mind, rather than the computer. Its creator, Yukihiro Matsumoto, wanted to create a programming language that was fun for programmers.
Ruby was first written in 1993 by Yukihiro "Matz" Matsumoto. Many of the design concepts were taken from Perl and SmallTalk. One of the unique things about Ruby is the core cultural principles associated with the language, much of which was influenced by Matz.
"I hope to see Ruby help every programmer in the world to be productive, and to enjoy programming, and to be happy. That is the primary purpose of Ruby language."
A well-written line of Ruby code can be read aloud, and a non-programmer should be able to understand it.
In the Ruby community, we try to focus on the people, not the machines.
Often people, especially computer engineers, focus on the machines. They think, "By doing this, the machine will run fast. By doing this, the machine will run more effectively. By doing this, the machine will something something something." They are focusing on machines. But in fact we need to focus on humans, on how humans care about doing programming or operating the application of the machines.
- *.rb
- Railsbridge & Rails Girls
- Seattle.rb
A couple of ideas that you may notice being different from other programming languages you may have tried:
- Object Oriented Programming (OOP) - the concept of "Objects" that have data fields to represent ideas within the program
- With inheritance & mixins (objects can be parents/children and siblings)
- Duck typing - the program infers the type of an argument or variable
When I see a bird that walks like a duck and swims like a duck and quacks like a duck, I call that bird a duck.
- Flexible syntax, there are many ways to write the exact same code.
Ruby can be directly executed from your terminal using IRB (Interactive Ruby). IRB is be a helpful tool for learning, quick computations, documentation, and debugging problems.
From the command line, enter irb. Once you're in IRB:
- Try inputting a string, like "hello world".
Did we just write the world’s shortest “Hello World” program? Not exactly. The second line is just IRB’s way of telling us the result of the last expression it evaluated. If we want to print out “Hello World” we need a bit more.
puts "hello world"
- Try doing some arithmetic in irb
2 + 32 * 32 ** 34/3(Note what Ruby does with the decimal places.)
Try this:
Math.sqrt(9)
- What's going on here?
A variable is just like "X" from high school algebra. It's a placeholder that stands in for a value.
a = 3 ** 2
b = 4 ** 2
Math.sqrt(a+b) => 5.0
We have used a lot of methods up to this point, and we didn't even know it!
In the Math.sqrt(9) example, sqrt is the name of a method. In this case, we **call** the sqrt method in the Math module with the parameter value 9.
As we continue on, we will use a lot of methods. Pretty soon, we'll be defining and using our own methods!