Arrays

Question 1

Array

Answer 1

• stores a list of variables
2 ways to declare them
Var array = […, ….];
var num = new array(….,….); //uncommon way to declare.
• you can have various types within an array.

Question 2

Element

Answer 2

• Each item inside an array

Question 3

Array Index

Answer 3

• Position number of an element inside an array

Question 4

embedded array

Answer 4

• An array within an array
• use “arrayName[2][0];
this example calls the index position of the embedded/inner array and the zero element within the index.

Question 5

.length

Answer 5

• a property that tells you how many elements there are in an array.
• the last index in an array is always the same number as the length of the array minus 1

Question 6

xxxx.push();

Answer 6

• adds element to the END of an array.

Question 7

xxxx.pop()

Answer 7

• removes an element from the END Of an array.

Question 8

xxxx.shift();

Answer 8

• removes an element from the beginning of an array

Question 9

xxxx.unshift(“item1”, “item2);

Answer 9

• Adds 2 elements to the beginning of an array.

Question 10

xxxx.splice(2, 2, “item1”);

Answer 10

• insert items and or delete items to an array.
• 1st number is index position where you want to start.
• 2nd number, number of elements to remove, starting with the first element that comes the element(s) that you’re splicing in.

Question 11

xxxx.slice(2, 4);

Answer 11

• copy one or more consecutive elements into a new array.
• 1st digit index of 1st element to be copied.
• 2nd digit is the index of the element after the last element to be copied.

Question 11

concat

Answer 11

• combine arrays together
• firstArray.concat(otherArray) will combine the elements in both arrays.
• To combine multiple arrays put the extra arrays inside the parentheses.
firstArray.concat(otherArray, moreArrays);
e.g.
var items = [1, 2];
var newItems = items.concat(3);

Question 12

xxxx.indexOf(“element”);

Answer 12

• takes an element and returns the FIRST index number where it can be found.
• multiple occurrences it will list the first one.
• returns -1 if not found.

Question 14

xxxx.forEach(function(element) {
// statement 
});

Answer 14

• JavaScript built in method of iterating through a for loop.
• Allows you to iterate an array faster instead of using a for loop.
• array.forEach(someFunction)