Javascript quick study Flashcards
remove from front
array.shift()
leave () blank
remove from back
array.pop()
leave () blank
add to front
array.unshift(new element)
add to back
array.push(new element)
absolute value
Math.abs(number) //always positive
round up
Math.ceil(number)
round down
Math.floor(number)
Generate random number
Math.random() * (max - min) + min)
leave () blank
Not
!
Or
||
And
&&
Equal to
===
Not equal to
!==
Get character in a string
“string”[index]
Get length
.length
Get an element in an array
array[index]
Is it an array
Array.isArray(input)
Add arrays together
array1.concat(array2, array3)
Turn a string into an array
“string”.split(“ “)
var name: “my name is”
name.split(“ “) = [“my”, “name”, “is”]
(“ “) means split at the space
Copy an Array
array.slice()
Access a value in an object
object[key]
Remove a property (key: value) from an object
delete object[key]
Average
Sum of numbers divided by amount of numbers
Example: 12 + 27 + 5 + 9 = 53. 53/5 = 10.6
Area of a Triangle
(Base x Height) / 2
Area of a Rectangle
Length * Width
Perimeter of a Circle
2 * Math.PI * radius
Code for PI
Math.PI
Area of a Circle
Math.PI * radius ** 2
Square Root
Math.sqrt(number)
