Fundamentals

Question 1

Variables

Answer 1

Any plain, lowercase word. Can consist of letters, digits, and underscores.

ex. ruby_123

Question 2

Numbers

Answer 2

Integer or series of digits. No commas but underscores allowed.

ex. 1 or -23 or 12_000_000

Question 3

Floats

Answer 3

Decimal Numbers or scientific notation

ex. 3.14 or 12.043e-04

Question 4

Strings

Answer 4

Any sort of characters(letters, digits, punctuation) surrounded by quotes.

ex. “sealab” or “These cartoons are great!”

Question 5

Symbols

Answer 5

Words that look like variables but start with a colon. Used in situations where you need a string but won’t be printing it to the screen.

Ruby responds quicker symbols then strings. (Pointers)

ex. :b or :ponce_de_leon

Question 6

Constants

Answer 6

Words like variables but are Capitalized. Variables are nouns then Contstants are proper nouns. Contstants can’t be changes once set.

ex. Time or Bunny_Lake

Question 7

Methods

Answer 7

Methods are verbs usually set to the end of a variable or contstant with a dot. They send a message. ! and ? Are allowed.

ex. front_door.open

Question 8

Method Argument

Answer 8

Arguments attached to the end of a method. Usually surround by a parentheses and separated by commas and can be chained – inner tubes

ex. front_door.paint( 3, :red ) .dry( 30 ) .close()

Question 9

Kernel Methods

Answer 9

Common methods that don’t use parentheses with arguments

ex. print “See, no dot.”

Kernel::print they are all class methods

p “See, no dot.” Also works for print

Question 10

Class/Instant Methods

Answer 10

Rather than a dot a double colon is used after variable or constant

ex. Door: :new( :oak ) Class method is new

Question 11

Global Variables

Answer 11

Begin with a dollar sign and good throughout your program no matter what class

ex. $1 or $chucky

Question 12

Instant Variables

Answer 12

Begin with @ and define the attributes of something. Think @ means attribute

ex. front_door with @width

Question 13

Class Variables

Answer 13

Double @@ used to define many related objects in a given class. @@ attribute all

ex. @@x is a class variable for all doors not just front_door

Question 14

Blocks

Answer 14

Any code surrounded by curly braces. A group of instructions you can use “do” or “end”

Scope is all information before block.

ex. 2.times { print “yes win!” }

Question 15

Block Arguments

Answer 15

Set of variables surrounds by pipe characters and separated by commas used at the beginning of a block. Tunnel in which variables enter the block

ex. |x,y|

Question 16

Ranges

Answer 16

2 values surrounded by parentheses and separated by ellipsis

ex. (1..5) is 1 through 5 or (‘a’..’z’)

If 3 … Used the last range is excluded (0…5) is 0 through 4

Question 17

Arrays

Answer 17

List surround by square brackets

ex. [1,2,5] or [‘coat’, ‘mittens’, ‘gloves’]

Question 18

Hashes

Answer 18

Dictionary surrounds by curly braces because they can be easy to search through. Unlike an array hashes are not kept in particular order. Keys => Values

ex. { ‘a’ => ‘aardvark’, ‘b’ => ‘badger’ }

code_words[‘a’] will return aardvark

Question 19

Regular Expressions (regexp)

Answer 19

Characters surround by slashes used to find words or patterns in text.

ex. /ruby/ or /[0-9]+/

Question 20

Operators

Answer 20

• % &&&raquo_space; are all examples

Question 21

Keywords

Answer 21

alias end BEGIN break end are all examples use them wrong will lead to syntax error

Question 22

===

Answer 22

Triple Equals is not as strict as ==

Great for looking for a value in a range

ex. 1905 === 19895..1913

Question 23

case..when statement

Answer 23

They must be used together.

case is followed by a value which is compared to when keywords

ex. case year
when 1984
“Born.”

Question 24

Scope

Answer 24

A field of vision inside methods and blocks.
Only the names inside the method are good for it’s scope.

ex.  opus_magum = true
       def Mom
           success = opus_magum
        end
opus_magum is out of Mom scope

Question 25

new

Answer 25

Method that creates a new, blank object. It also calls the initialize method automatically.

ex. todays_wishes = Wishmaker.new

Question 26

Ruby

Answer 26

Everything is an object,

1. You define things
2. Then you put them into action

Question 27

: :

Answer 27

Class methods are usually called with a double colon but a period is fine as well.

ex. Elevator: :maintenance_password

Question 28

backtrace

Answer 28

When you get an error the most important aspect is the beginning

Question 29

Nil

Answer 29

Without value and it can never be “true”

Ex. plastic_cup = nil

Question 30

unless

Answer 30

Will show “nil” and “false”

The opposite of “if” which will not

*If a is true and b is not true

Ex. If plastic_cup unless glass_cup

Question 31

==

Answer 31

Id check and is method

Ex. If carrot == true
print “I love vegetables”
end

Question 32

«

Answer 32

Concatenation operator which means to append or add to the end

Question 33

gets

Answer 33

Kernel methods that will respond with a sting of what was typed

Question 34

[ ]

Answer 34

Index for a hash to find definition in a hash

Question 35

each

Answer 35

Method for arrays, hashes, and strings. It will go through each item

Question 36

gsub

Answer 36

Global substitution which will search and replace.

Ex. idea.gsub! (real, code )

Question 37

strip

Answer 37

Method that Removes all additional spaces and blank lines in a string

Question 38

File Class Methods

Answer 38

File::read( “file_name.txt” )

File::rename( “file_name.txt” , “file_name1.txt” )

File::delete( “file_name.txt” )

‘w’ = new file ‘r’ = read ‘a’ = add

Question 39

sort_by

Answer 39

A method that iterates or cycles through a list of things

Other methods are next and break

Question 40

Domination

Answer 40

Learning how to use the answers methods give back

Question 41

elseif

Answer 41

Used when u want to see if an object is true or false.

Question 42

next

Answer 42

Used to skip to the next item in a list

Question 43

break

Answer 43

Kicks you if an iterating loop

Question 44

def

Answer 44

Used to define methods

Question 45

Class

Answer 45

Used to define classes