JS Operators and Methods

Question 1

not

Answer 1

!

Question 2

or

Answer 2

||

Question 3

and

Answer 3

&&

Question 4

how do you create a combination of booleans?

Answer 4

() for example
true && (true || false)
will derive true

Question 5

equal to

Answer 5

===

Question 6

not equal to

Answer 6

!==

Question 7

addition

Answer 7

+

Question 8

subtraction

Answer 8

-

Question 9

multiplication

Answer 9

*

Question 10

division

Answer 10

/

Question 11

exponent

Answer 11

**

Question 12

modulo

Answer 12

%

Question 13

plus equals

Answer 13

\+=
example:  
x += y
x = x + y
incrementing x by y

Question 14

minus equals

Answer 14

-=

Question 15

times equals

Answer 15

*=

Question 16

divide equals

Answer 16

/=

Question 17

absolute value

Answer 17

Math.abs( )

Question 18

round up

Answer 18

Math.ceil( )

Question 19

round down

Answer 19

Math.floor( )

Question 20

parsing an integer

Answer 20

parseInt( )

Question 21

parsing a float

Answer 21

parseFloat( )

Question 22

generate a number between 0 and 1

Answer 22

Math.random( )

Question 23

greater than

Answer 23

>

Question 24

greater than or equal to

Answer 24

> =

Question 25

less than

Question 26

less than or equal to

Answer 26

<=

Question 27

accessing a character in a string

Answer 27

string[index]
note: the index is the number that corresponds to the location of the character in the string. strings start at 0 in javascript.

Question 28

reassigning a string

Answer 28

leave off var, let or const and reassign the variable to the new value;
e.g. 
var someVarable = "something";
someVariable = "reassigned string";

Question 29

concatenate two or more strings

Answer 29

+

Question 30

string interpolation

Answer 30

+ string interpolation +

Question 31

get the length of a string

Answer 31

.length

Question 32

get the last character of a string

Answer 32

[ .length - 1]

e.g. “string”[“string”.length - 1]

Question 33

get a portion of a string

Answer 33

.substring(first index, last index]
i.e. “string”.substring(3, 4);
would derive “in”

Question 34

find where a portion of the string exists in a string

Answer 34

.indexOf( )
i.e. “string”.indexOf(“in”);
would derive 3
if it doesn’t exist, it derives -1

Question 35

turn a value into a string

Answer 35

.toString( )

Question 36

escape characters

Answer 36

\

Question 37

new line

Answer 37

\n

Question 38

create an array

Answer 38

[ ]

Question 39

access an element in an array

Answer 39

array name [index of element]
e.g.
var array = [1, 2, 3, 4];

var secondElement = array[1];
console.log('secondElement:', secondElement)

Question 40

reassigning an element in an array

Answer 40

array name [index] = “new value”;

note: arrays are mutable

Question 41

length of an array

Answer 41

.length

Question 42

last element of an array

Answer 42

array name[array name.length - 1]

almost identical to getting the last element in a string

Question 43

adding an element to the back of an array

Answer 43

.push( )

Question 44

removing an element from the back of an array

Answer 44

.pop( )

Question 45

adding an element to the front of an array

Answer 45

.unshift( )

Question 46

removing an element from the front of an array

Answer 46

.shift( )

Question 47

adding an element in general to an array

Answer 47

.splice(index, 0, adding element)
e.g.
var array = [1, 2, 4];
array.splice(2, 0, 3);
derives 1,2,3,4

Question 48

removing an element in general from an array

Answer 48

.splice(index, number of removing elements, adding elements if there are any)

Question 49

determine if a value is an array

Answer 49

Array.isArray( )

Question 50

taking parts of an array and creating a new array

Answer 50

.slice(start, end);

Question 51

add an array to another array

Answer 51

.concat

first array.concat(second array);

Question 52

transform an array into a string

Answer 52

.join( ) all elements added together into a string
.join(“ “) adds spaces
.join(“-“) would add a dash between each element

Question 53

transform a string into an array

Answer 53

.split( ) all elements added together in an array
.split(“ “) all elements added individually in an array
.split(“-“)if elements have dashes, it will add them individually in an array

Question 54

determine where in an array we can find a particular element

Answer 54

.indexOf( )