Ruby

Question 1

how to comment in ruby?

Answer 1

#

Question 2

how to print in ruby?

Answer 2

puts and has a new line returns nil
p returns the argument
print no new line

Question 3

what does puts return?

Answer 3

nil as in ruby everything returns something

Question 4

how to define a variable?

Answer 4

gretting = ‘hello world’

Question 5

how to define a function?

Answer 5

def greeting(say_something)
puts ‘hello’
end

Question 6

can u call a function before u define it?

Answer 6

no u must define it first

Question 7

what is the difference between single quotes and double quotes?

Answer 7

with single quotes u can’t do string interpolation

Question 8

how to concatenate strings?

Answer 8

with +

Question 9

how to do string interpolation?

Answer 9

with “ #{variable} “

Question 10

how to know the type of the variable?

Answer 10

variable.class

Question 11

what is an important rule in ruby?

Answer 11

everything is an object

Question 12

how to know the built in methods for a variable?

Answer 12

variable.methods

Question 13

how to convert a variable to a string?

Answer 13

variable.to_s

Question 14

can u chain methods in ruby?

Answer 14

yes

Question 15

how to know the length of a variable?

Answer 15

variable.length

Question 16

how to reverse a string?

Answer 16

variable.reverse

Question 17

how to capitalize a variable?

Answer 17

variable.capitalize

Question 18

how to check if a variable is empty?

Answer 18

variable.empty?

Question 19

how to check if a variable in nil?

Answer 19

variable.nil?

Question 20

how to replace a part of a string?

Answer 20

variable.sub

Question 21

what is the difference between sub and gsub?

Answer 21

gsub replaces multiple occurances

Question 22

what happens when u assign a variable to another variable?

Answer 22

they are both pointing to the same place in memory and if u change one variable the other don’t cuz he is still pointing to that place in memory

Question 23

what is a simple solution for loops?

Answer 23

number.times{}

Question 24

how to generate a random number?

Answer 24

rand()

Question 25

how to take input from the user?

Answer 25

gets.chomp

Question 26

what is the method used to compare types?

Answer 26

10.eql?(10)

Question 27

how to create an array?

Answer 27

a = [1 , 2 , 3]

Question 28

what happens when u use puts to print an array?

Answer 28

u print every element in a new line

Question 29

how to access the last element of an array?

Answer 29

a.last

Question 30

how to create a range?

Answer 30

1..100

Question 31

what is ruby all lower case?

Answer 31

it’s a computer program (interpreter) that is used to run and execute ruby files

Question 32

what is irb?

Answer 32

interactive ruby console program

irb –simple-prompt

Question 33

types of variables?

Answer 33

1 - local variables: write them with underscore
2 - instance variables: storing informtation in individual objects and starts with @
3 - class variables: start with @@ and store information on the class hierarchy
4 - global variables: start with $
5 - constants: starts with Uppercase FirstName or FIRST_NAME
6 -

Question 34

what is intentional about methods?

Answer 34

that it blends with the code it was meant to not know whether it’s a variable or a method call and it follows the local variable semantics but end with ? or ! or =

Question 35

how do u construct an object?

Answer 35

whether by a literal like the string using ‘ ‘

(quotation) or binding the object to a variable

Question 36

can u call a method without using parenthesis?

Answer 36

yes

Question 37

what is a bareword call?

Answer 37

puts ‘Hello’

Question 38

what does a class define?

Answer 38

the functionality of an object that is created from that class

Question 39

is class or object more important?

Answer 39

the object because it can acquire and change behavior after t’s initialized

Question 40

what is the class responsible for?

Answer 40

launching the object into existence a process knows as instantiation

Question 41

how to run a syntax check on a ruby program?

Answer 41

ruby -cw name.rb

Question 42

what does the -c flag do?

Answer 42

check for syntaxt

Question 43

what does -w flag do?

Answer 43

check for higher illegalities

Question 44

what is the function used to read from a file?

Answer 44

File.read();

Question 45

what is the function used to write to a file?

Answer 45

File.new();

Question 46

what is the key to using extensions and libraires?

Answer 46

require method , along with it’s near relation load. these methods allow you to load extensions at run time

Question 47

Feature, extension, or library?

Answer 47

we require a feature

Library is more concrete and more common. It connotes the actual code as well as the basic fact that a set of programming facilities exists and can be loaded

Extension can refer to any loadable add-on library,
but it’s often used to mean a library for Ruby that’s been written in the C programming

Question 48

what happens when u call load?

Answer 48

u read the second file and If the file you’re loading is in your current working directory, Ruby will be able to find
it by name. If it isn’t, Ruby will look for it in the load path.

A call to load always loads the file you ask for, whether you’ve loaded it already or not.
If a file changes between loadings, anything in the new version of the file that rewrites or overrides anything in the original version takes priority.

Question 49

what is a loading path?

Answer 49

is a list of directories in which it searches for files you ask it to load. You can see the names of these directories by examining the contents of the special global variable $: (dollar-colon).

Question 50

what is one major difference between load and require?

Answer 50

require, if called more than
once with the same arguments, doesn’t reload files it’s already loaded. Ruby keeps
track of which files you’ve required and doesn’t duplicate the effort

Question 51

what is more abstract require or load?

Answer 51

require as u don’t require a file u require a feature and u don’t have to specify the extension on the filename

Question 52

what does require allow u to do?

Answer 52

require allows you to treat

extensions written in Ruby the same way you treat extensions written in C

Question 53

what do u use more require or load?

Answer 53

require

Question 54

what do we use to include files in relative path?

Answer 54

require_relative