02. Ruby Basic slides - Ruby Core Teaching
- 2. Contents COMMENT BLOCK, PROC & LAMBDA DATA TYPES VARIABLE LITERAL OPERATORS KEYWORD
- 3. Comment
- 4. Comment Use for code notes. Not translated by interpreter. NORMAL COMMENT While comments are typically ignored by Ruby, special “magic comments” contain directives that affect how the code is interpreted. MAGIC COMMENT
- 6. Variables
- 7. Variables A VARIABLE IS SIMPLY A NAME FOR A VALUE. VARIABLES ARE CREATED AND VALUES ASSIGNED TO THEM BY ASSIGNMENT EXPRESSIONS. Global variable - $ sign Instance variable - @ sign Class variable - @@ sign Local vatiable - no sign Constants - Capital letters KINDS OF VARIABLES:
- 10. Class Variables
- 11. Local Variable
- 12. Constant
- 13. Literal
- 14. Literal
- 15. Block, Proc & Lambda
- 16. Block, Proc & Lambda A very important concept that most of Ruby programmers misunderstand(including the slides maker!) The only ones that definitely understand the concept are the Ruby committers and Rails committers!
- 17. Block A way to group lines of code together Blocks are enclosed in a do / end statement or between brackets {}, and they can have multiple arguments. Syntax Including conditional statement:
- 18. Block Yield is a Ruby keyword that calls a block when you use it. When you use the yield keyword, the code inside the block will run & do its work.
- 19. Block Widely used in Ruby more than Proc and Lambda Advantages Simple, easy to use Disadvantages One time use only (New block must be generated when input changed) Leads to code duplication
- 20. Proc Proc is an object that should be stored in a variable Proc is essentially just a named block to be reuse multiple times → Overcome the disadvantages of block
- 21. Lambda Lambda is a function with no specific name Object of Proc class Return a value Used to assign a piece of code Syntax: Example:
- 22. Lambda Object of Proc class, so when using, use call:
- 23. Operators
- 24. ! + - ~ * ** / % << >> & | ^ == === != <=> >= > < <= = %= /= -= += *= **= .. ... not and or ?: && || Operators
- 25. Keyword
- 26. Keyword Priority words in Ruby Usually used as commands to perform an action When set name for variable, do not match the keyword name
- 27. alias and BEGIN begin break case class def defined? do else elsif END end ensure false for if in module next nil not or redo recuse retry return self super then true undef unless until when while yield Keyword
- 28. Data type
- 29. Data type Boolean Symbol Integer, Float, Rational Number Nil value: A singleton object of a NilClass. Represents the absence of value.(In other programming languages, it is a null) String Arrays and Hashes Read more in the https://ruby-doc.org/