Ruby introduction part1 from Brady Cheng
[Quick Review]
Numbers
Integer, a series of digits which can start with a plus or minus sign.
1 , 23 , and -10000 are examples
population = 12_000_000_000 is also an example.
Float, consists of numbers with a decimal place or scientific notation.
3.14 , -808.08 and 12.043e-04 are examples
Strings
Any sort of characters (letters, digits, punctuation) surrounded by quotes. Both single and double quotes are used to create strings.
"sealab" , '2021' , or "These cartoons are hilarious!" are examples.
Symbols
Like variables. contain letters, digits, or underscores. But start with a colon. Symbols are lightweight strings. Usually, symbols are used in situations where you need a string but you won’t be printing it to the screen.
:a , :b , or :ponce_de_leon are examples.
Constants
Constants are words like variables, but constants are capitalized.
Time , Array or Bunny_Lake_is_Missing are examples.
Variables
Any plain, lowercase word is a variable. Variables may consist of letters, digits and underscores.
x , y , banana2 or phone_a_quail are examples.
Global variables
Variables which begin with a dollar sign are global.
$x , $1 , $chunky and $CHunKY_bACOn are examples.
Instance variables
Variables which begin with an at symbol are instance variables. Instance variables are used to define characteristics of a single object. Think of the at symbol as meaning attribute.
Class variables
Variables which begin with double at symbols are class variables. class variables give an attribute to many related objects in Ruby. Think of the double at prefix as meaning attribute all.
@@x , @@y are examples.
[Quick Review]
Numbers
Integer, a series of digits which can start with a plus or minus sign.
1 , 23 , and -10000 are examples
population = 12_000_000_000 is also an example.
Float, consists of numbers with a decimal place or scientific notation.
3.14 , -808.08 and 12.043e-04 are examples
Strings
Any sort of characters (letters, digits, punctuation) surrounded by quotes. Both single and double quotes are used to create strings.
"sealab" , '2021' , or "These cartoons are hilarious!" are examples.
Symbols
Like variables. contain letters, digits, or underscores. But start with a colon. Symbols are lightweight strings. Usually, symbols are used in situations where you need a string but you won’t be printing it to the screen.
:a , :b , or :ponce_de_leon are examples.
Constants
Constants are words like variables, but constants are capitalized.
Time , Array or Bunny_Lake_is_Missing are examples.
Variables
Any plain, lowercase word is a variable. Variables may consist of letters, digits and underscores.
x , y , banana2 or phone_a_quail are examples.
Global variables
Variables which begin with a dollar sign are global.
$x , $1 , $chunky and $CHunKY_bACOn are examples.
Instance variables
Variables which begin with an at symbol are instance variables. Instance variables are used to define characteristics of a single object. Think of the at symbol as meaning attribute.
@x , @y are examples.
Variables which begin with double at symbols are class variables. class variables give an attribute to many related objects in Ruby. Think of the double at prefix as meaning attribute all.
@@x , @@y are examples.
