Ruby in 100 Minutes (notes)

These are my notes from reading Ruby in 100 Minutes.

Note: I’m only making notes on things that were new to me while reading this. You may learn a lot of interesting stuff if you read the actual source, rather than my notes.

Lessons Learned

Ruby was originally developed by a developer named Matz in 1994 but it didn’t get popular until six years later, when it became a popular programming language in Japan. It remained a Japanese programming language (meaning there was no english documentation for it) until 2004/5 when 37signals empowered an engineer to use the language to build BaseCamp.

Now it’s a popular programming language.

“Ruby is an “interpreted” programming language which means it can’t run on your processor directly, it has to be fed into a middleman called the “virtual machine” or VM.” – JumpStartLabs

Virtual machine is either the IRB (which to me is a stage we go into via the terminal by typing irb + enter) or executing the programs via the command line.

Ruby reads right to left.

Ruby variable should be named after the meaning of their contents, not the type

Don’t include the word “array” when labeling arrays

For example: chocolate_types_array should be chocolate_types

Also, don’t abbreviate. Just spell stuff out.

For example: bkry_reno  should be spelled out to bakery_reno

When selecting positions in an array, you can use negative numbers to select from the back of the string.

For example: with the string greeting = “123456789”

Prints 345678

Prints 34567

String Concatenation

“hello, ” + variable | “!”

String Interpolation
name = "Ned"
puts "Good day, #{name}!"
#prints Good day, Ned!

Note: Interpolation tends to be shorter than Concatenation…

“Symbols are difficult to explain” – They are halfway between a string and a variable? They look like this:


Run the following through terminal… it’s crazy:

There is a lot going on in there… going to have to come back to this…

Think of a symbol as a “named integer.”

Two kinds of numbers – Integers (whole numbers) and Floats (have decimal points)

What does this mean – “Because Ruby’s integers are objects they have methods.” – I don’t get it.
5.times do
puts "hello, world!"

Simple. This just prints “Hello, world!” 5 times

Blocks are Sets of Instructions – Blocks = parameter passed into a method call


Blocks can be written many different ways.

Bracket Blocks = 5.times{ puts “Hello, World!” }


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