try ruby

Question 1

reverse a string

Answer 1

.reverse

Question 2

length of a string

Answer 2

.length

Question 3

print string x times

Answer 3

”” * X

Question 4

reverse number

Answer 4

1.to_s.reverse

Question 5

to string

Answer 5

.to_s

Question 6

to integer

Answer 6

to_i

Question 7

to array

Answer 7

to_a

Question 8

declare array / assign array

Answer 8

[] / x=[1,2,3]

Question 9

[] creates an empty what

Answer 9

list

Question 10

does a list store thing out of order

Answer 10

false

Question 11

get max from array

Answer 11

.max

Question 12

sort array

Answer 12

.sort!

Question 13

method with ! does what

Answer 13

changes value for good

Question 14

replace all string x in an array containing x

Answer 14

arr[‘x’]=’y’

Question 15

reverse an array with a string of lines, (only each individual line) without writing words backwards

Answer 15

poem.lines.to_a.reverse

Question 16

join elements in an array

Answer 16

.join

Question 17

check to see if something is included

Answer 17

.include?

Question 18

lowercase everything

Answer 18

.downcase

Question 19

delete an obj

Answer 19

.delete

Question 20

dictionary or hash

Answer 20

books={}

Question 21

add elements to a dictionary/hash

Answer 21

books[“title”] = :splendid

Question 22

can you use length on a dictionary/hash?

Answer 22

yes, will return number of items within

Question 23

iterate through a dictionary/hash’s values

Answer 23

books.values.each{|rate| ratings[rate]}

Question 24

iterate and count number of times rate appears through a dictionary/hash’s values

Answer 24

books.values.each{|rate| ratings[rate]+=1}

returns like {:good=>2, :bad:=>5}

Question 25

how do you create a block in ruby

Answer 25

curly braces

Question 26

a way of performing something x times

Answer 26

5.times {print “hi! “}

Question 27

how to create a symbol

Answer 27

:symbolhere

Question 28

blocks

Answer 28

chunk of code which can be tacked oon to many of rubys methods

Question 29

access directory

Answer 29

Dir.entries “/” (anything listed after a method is called an attatchment, like the / in this example)

Question 30

Dir[] does what

Answer 30

searches for files with wildcard characters

Question 31

read a file

Answer 31

File.read()

Question 32

copy a file to new dir

Answer 32

FileUtils.cp(‘file1’, ‘destination’)

Question 33

open file

Answer 33

File.open()

Question 34

using the pipe character in a do statement

Answer 34

File.open(“txt.txt”, “a”) do |f|
f&laquo_space;“Cat”
end

Question 35

check when a file was changed

Answer 35

File.mtime(filename.txt)

can also append .hour to it to just get hour

Question 36

how are arguments seperated in ruby

Answer 36

commas

Question 37

define a method in ruby

Answer 37

def methodname
code
end

Question 38

split

Answer 38

method for strings, breaking it into an array based on the given char to split on

Question 39

strip

Answer 39

removes extra whitespace around the url

Question 40

p line is short for what

Answer 40

paragraph

Question 41

create a list

Answer 41

list do
p”1”
p “2”
end

Question 42

to load a library

Answer 42

require ‘library’

Question 43

the .new method does what

Answer 43

used to make objects of a certain class

Question 44

define a class

Answer 44

class Nameofclass

Question 45

How to instantiate a class

Answer 45

x=NAmeofclass.new

Question 46

what is attr_accessor

Answer 46

attributes or variables attatched to the class, used for acccesing outside the class

Question 47

how to declare an instance variable

Answer 47

@x

Question 48

what are instance variables

Answer 48

vars for accesing inside the class

Question 49

sort attributes with a time association in ascending order

Answer 49

blog.sort_by { |entry| entry.time }.reverse

Question 50

add new entries

Answer 50

&laquo_space;x

Question 51

what can the map method do

Answer 51

cycle through an array and replace each item with something new

Question 52

Time method

Answer 52

Time.now

Time.now-2.weeks

Question 53

use a variable in a string

Answer 53

“Hello #{variable}”

Question 54

execute a block of code x times

Answer 54

x.times do
code
end

Question 55

iterate through an array

Answer 55

array.each do |n|
puts n
end

Question 56

unless

Answer 56

evaluates to if not, do

Question 57

an if, else if, else statement in ruby

Answer 57

if x==0
  puts x
elsif x==1
  puts x
else
 puts x
end

Question 58

.empty?

Answer 58

boolean for if something is empty

Question 59

nil is treated as what in ruby

Answer 59

false

Question 60

path of a file method

Answer 60

.file_path

Question 61

empty strings, 0, and empty arrays are treated as what

Answer 61

true

Question 62

fail raises what kind of error if true

Answer 62

runtimeerror

written fail “wrong password”

will raise exception wrong password

Question 63

what hapens in result= 1||2

Answer 63

returns 1, because it doesnt need to evaluate the second half

Question 64

create an array using ||

Answer 64

tweets=timeline.tweets||[]

if tweets returns nil, it creates an array otherwise it assigns them

Question 65

does every method in ruby return a value

Answer 65

yes

Question 66

case statements in ruby

Answer 66

case, when, then, else, end

Question 67

use grep method in ruby

Answer 67

search = "Super Mario Bros."
games = ["Super Mario Bros.", "Contra", "Metroid", "Mega Man 2"]
matched_games = games.grep(Regexp.new(search))

Question 68

uppercase all letters

Answer 68

.upcase on stringleas

Question 69

are variables an object

Answer 69

kind of, its a reference to an object (east previous to ruby 2)

Question 70

ruby convention for naming variable

Answer 70

underscores betweeen words

Question 71

class variable indicator

Answer 71

@@

Question 72

instance variable indicator

Answer 72

@

Question 73

exponential operator

Answer 73

**

Question 74

find class type of something

Answer 74

.class

Question 75

what operator appends an item to an array

Answer 75

«

Question 76

ruby is inspired by

Answer 76

perl, smalltalk, eiffel, ada

Question 77

ruby is a blank language

Answer 77

dynamic

Question 78

when ruby runs, it is translated and executed how

Answer 78

on the fly

Question 79

what is the standard ruby interpreter

Answer 79

MRI (alternative:rubinius amd jruby, whihc runs on java vm)

Question 80

to run ruby what do you need

Answer 80

a ruby interpreter

Question 81

in ruby what is repl

Answer 81

read evaluate print loop

Question 82

in ruby what is the => operator called

Answer 82

hash rocket

Question 83

in ruby 1.9.3 how many reserved words are there

Answer 83

40

Question 84

what are the 4 types of variables in ruby 1.9.3

Answer 84

local, global, instance, constant

Question 85

in ruby how do you define a global variable

Answer 85

$– can be cap or lowercase

Question 86

in ruby how do you define a constant var

Answer 86

all upercase

Question 87

in ruby how do you define a instance variable

Answer 87

@

Question 88

in ruby what is the difference bw an instance variable and a local

Answer 88

instance variables are accesible throughout the class

Question 89

in ruby an class typically uses what case struct

Answer 89

camel, upper first too

Question 90

how to define a case statement in ruby

Answer 90

case

when x

Question 91

in ruby, def initialize is like what

Answer 91

a constructor

Question 92

in ruby how can you output the value of a variable from within a sting

Answer 92

using the#{var} // this is called interpolation– if wrapped in single quotes, this will not work

Question 93

in ruby how do we get input from the user

Answer 93

the gets method

Question 94

inrubywhat does chomp do

Answer 94

removes whitespace

Question 95

3 ways to create a string in ruby

Answer 95

String.new(), single quotes, double quotes

Question 96

in ruby when using single quotes, do you need an escape for example a double quote?

Answer 96

no

Question 97

what are 3 concatination operators for strings in ruby

Answer 97

&laquo_space;and + and .concat

Question 98

if using the [n] on a string like name[0] what does it return

Answer 98

the ascii representaton of that letter

Question 99

in ruby what is the method for removing trailing whitespace

Answer 99

.chop

Question 100

how to find the index of a letter in a string ruby

Answer 100

.index(“x”)

Question 101

in ruby how do you find how many letters are in the string

Answer 101

.length or .size

Question 102

in ruby how do you find what is swapcase

Answer 102

swaps upper for lower and vice versa

Question 103

in ruby what does split do

Answer 103

returns an array split on the given value .split(“ “)

Question 104

runnin g .size in ruby on a fixnum (i) what is returned

Answer 104

the bytes it takes up

Question 105

in ruby what is a combined operator comparison symbol and what does it return

Answer 105

0 if equal 1 is lef is greater -1 if right is greater

Question 106

in ruby the .eql? does what

Answer 106

checks if the value AND type are the same

Question 107

how to access values in a library

Answer 107

libname::x

Question 108

how to generate a random number in ruby

Answer 108

rand (addditonally you can use a follow number to find rand between 0->x)

Question 109

to use a library in ruby what do you do

Answer 109

require “lib”

Question 110

in ruby bigdecimal fixes what

Answer 110

the floating point math problem

Question 111

in ruby how to use make a floating umber to bigdecimal

Answer 111

BigDecimal.new(x)

Question 112

in ruby [1,2,3]&[2,3] wpold return what

Answer 112

[1]

Question 113

in ruby how to put values at the beginning of an array

Answer 113

unshift(x)

Question 114

how to clear an array in ruby

Answer 114

.clear

Question 115

in ruby how to flatten a multi-d array

Answer 115

.flatten!

Question 116

what does array.select do with a given block, what about reject and any and all

Answer 116

returns values iwthin the array that are validaated as true. i.e array.select {|item| item>x}

alternatively you can use reject to basically perform a !=

any? and all? return booleans – selef explanatory on when it would return t/f

Question 117

in a ruby hash how can you find a single element, what about all elements that match? You can allso use .all

Answer 117

hash. find{|key,value| key==’x’} //returns array
hash. find_all{|key,value| value.match(‘x’)} //returns array

You can allso use .all? and any for their boolena return

Question 118

how to find how many values are in a has

Answer 118

.any method

Question 119

how to convert a hash to an array

Answer 119

hash.map{| key, value| value =”(hash) #{value}”} //returns an array with the hash in parenthesis prepended to the value [“(hash) value”, “(hash) value2)”]

Question 120

do ruby methods accept default values

Answer 120

yes

Question 121

in ruby how do you create a class method

Answer 121

prefix it with the word self //self.method

Question 122

in ruby what does ||= do

Answer 122

this is a conditional assignment operator– for example it checks if it exists, and if it doesnt, then it does

Question 123

in ruby what is the way to set a set and get method

Answer 123

attr_reader/writer :x

or

attr_accesor

Question 124

what s=is an alternate way of creating a group of class methods without using self on each method

Answer 124

class << self
 def method
 end
 def method2
 end
end

Question 125

in ruby how do you make a private method

Answer 125

define the method normally, and then use private :method at the end, or you can use the word private above all private methods

Question 126

in ruby methods have what protection level by default

Answer 126

public

Question 127

in ruby how can a class call its own private method

Answer 127

creating a new public method that has the private method nested within the body
def call_private
private_method
end

Question 128

in ruby what is a protected method

Answer 128

protected methods can be called within the class and by other objects/subclasses

Question 129

in ruby how do you write a forloop

Answer 129

for i in array do
x
end

Question 130

in ruby what is the keyword that skips to the next iterationn oif the loop

Answer 130

next

Question 131

in ruby what is the keyword that breaks out of a loop entireley

Answer 131

break

Question 132

how can you run a loop until a certain value is gotten without using the until loop

Answer 132

loop do combined with break

Question 133

in ruby what does retry do? what about redo

Answer 133

retry reexecutes the entire loop, redo will only redo the current iteration it is on until end

Question 134

In ruby how do we pass a block into a method

Answer 134

method(&blockname)

Question 135

in ruby how do you create a block

Answer 135

curly braces, or do and end (curly braces have a higher priority

Question 136

in ruby how do you call a block

Answer 136

the call method

Question 137

in ruby what is the method to check if a block was passed to a method

Answer 137

block_given?

Question 138

in ruby what is the keyword to make sure something is given (in error checking)

Answer 138

ensure

Question 139

in ruby how do you raise an error

Answer 139

using the raise keyword followed by an error

Question 140

in ruby if an error is expcted what can we use to counter it

Answer 140

using the rescue statement

Question 141

in ruby what do BEGIN and END blocks do

Answer 141

BEGIN is run at the beginning of a program, end is run at the end of a program

Question 142

in ruby what does yield do

Answer 142

The yield statement gives control of the current method over to the block that is passed in. Yield can also be used to send a variable value in to, or out of, a block of code

Question 143

in ruby how do you create a proc

Answer 143

proc.new with a block
Proc.new{block here}

or you can use lower case proc with block assigned to a variable

Question 144

in ruby how do you create a lambda

Answer 144

similar to proc, you assign a variable to lambda { block here}

you can also use the skinny arrow ->{ block }

Question 145

in ruby how does a proc take an argument

Answer 145

using the pipes. mproc= proc {|passedin| }

Question 146

in ruby what is the major difference between a proc and a lambda

Answer 146

lamdas require the exact number of arguments specified, also a specified return in a proc prior to the final line will return that, whereas a lamda will return the final return value

Question 147

in ruby how do you write multi line comments

Answer 147

=begin

=end

Question 148

in ruby what does capitalize do

Answer 148

capitalizes the first lettter

Question 149

in ruby what is the naming convention and keyword to create a new module

Answer 149

module in camelcase (first upper too)

Question 150

in ruby, what naming convention do you use to create a constant

Answer 150

all uppercase

Question 151

In ruby (specifically irb) what symbols do you use to access something from within a loaded module

Answer 151

::

Question 152

in ruby modules are primarily used to accomplish what

Answer 152

namespacing

Question 153

in ruby what does extending allow us to do in terms of modules and classes

Answer 153

using .extend, a class can access a modules internals

Question 154

in ruby, alternative to using extend to access methods inside a module, what can we do

Answer 154

include the module inside the class

Question 155

what is the main difference between a symbol and string in ruby

Answer 155

a symbol only exists once in memory for a session

Question 156

in ruby how can we override default methods for instance to_S

Answer 156

within a classs, you can create a to_s method