w1d1

Question 1

creating arrays

Answer 1

empty_array = Array.new
empty_array = []

Question 2

accessing item by index (array)

Answer 2

some_fruits = [“pear”, “apple”]
some_fruits[0]
some_fruits[-1] from end

Question 3

array ‘range’ example

Answer 3

some_fruits[0..1], some_fruits[0…2]
.. => start to finish
… => start to, but not including finish

Question 4

accessing elements in order

Answer 4

array.each do |thing|

Question 5

you should never modify array during iteration

Answer 5

true

Question 6

setting and adding elements (array)

Answer 6

array[1] = “something else”
array &laquo_space;“something”
array.push “something”

Question 7

array + array

Answer 7

creates a new array that hold both values

Question 8

add two arrays without ‘+’

Answer 8

array.concat(array_other)

Question 9

array size example

Answer 9

array.count

Question 10

check if array is empty

Answer 10

array.empty?

Question 11

push pop array

Answer 11

array &laquo_space;“something”

array.pop

Question 12

array as queue example

Answer 12

array &laquo_space;elements
array.shift
(first in, first out)

Question 13

push element in front of array

Answer 13

array.unshift

Question 14

interpolation

Answer 14

execute code in #{} inside string

Question 15

finding elements in array

Answer 15

array.include?(something)

Question 16

finding index of element in array

Answer 16

array.index(something)

Question 17

sorting an array

Answer 17

array. sort (returns new array)

array. sort! (modifies array)

Question 18

randomize order of array

Answer 18

array.shuffle

Question 19

access first and last element of array

Answer 19

array. first

array. last

Question 20

select element at random in array

Answer 20

array.sample

Question 21

arrays should always contain one type of something

Answer 21

true

Question 22

TQ: remove duplicates from array

Answer 22

enter

Question 23

TQ: sum of two positions in array that equal zero

Answer 23

enter

Question 24

TQ: Tower of Hanoi

Answer 24

enter

Question 25

TQ: My Transpose

convert square grid rows to col

Answer 25

enter

Question 26

TQ: Stock Picker

Answer 26

enter

Question 27

escape character example

Answer 27

\n, \, ", '

Question 28

reverse order of string

Answer 28

string.reverse

Question 29

uppercase string

Answer 29

string.upsace

Question 30

lowercase string

Answer 30

string.downcase

Question 31

appending string

Answer 31

string &laquo_space;“another string”

does not create new string object. it just modifies existing one

Question 32

access substring

Answer 32

string[5..6]

Question 33

string length

Answer 33

string.length

Question 34

split string into arrays

Answer 34

string. split(“, “) split by comma

string. split(“ “) split by space

Question 35

nil.to_s

Answer 35

””