Part 3- A Smarter Way to Learn JavaScript

Question 1

What are the rules for naming an array?

Answer 1

array names have the same naming conventions as other variables

Question 2

What types of data can an array hold?

Answer 2

Same as any other variable: strings, numbers, variables

Question 3

Can you mix data types in the same array?

Answer 3

Yes.

Question 4

Which punctuation is used in an array?

Answer 4

*the list of elements has square brackets: [],

*you separate elements in the list with a comma and a space

*in an array of strings, the comma between elements goes AFTER the quotation mark.

Question 5

In an array, what’s another name for a value?

Answer 5

an element

Question 6

How do you formally refer to a specific element in an array?

Answer 6

The array’s name
followed by the index number inside of straight brackets

For example, cities[5] would be how you refer to the sixth element in an array called CITIES

Question 7

What’s the keyword to add elements to the end of an array?

Answer 7

*push()

*arrayname.push(elements);

*Think of it as “push parentheses”

Question 8

What’s the keyword to remove the last element of an array?

Answer 8

pop();
arrayname.pop();
Think of it as “pop parentheses”

Question 9

Do you have to add all elements to an array in order?

Answer 9

No.

Question 10

What happens if you call an element and it hasn’t been assigned?

Answer 10

It will return “undefined.”

Question 11

What are the six keywords used to change the elements in an array?

Answer 11

pop()
push()
shift()
unshift()
splice()
slice()

*Each of these methods RETURNS a value. When we get to the W3Schools tutorial, I’ll learn which value each returns

Question 12

What do pop() and shift() have in common?

Answer 12

They both remove elements from an array

Question 13

What do push() and unshift() have in common?

Answer 13

They both add elements to an array

Question 14

What do pop() and push() have in common?

Answer 14

They both work at the end of an array

Question 15

What do shift() and unshift() have in common?

Answer 15

They both work at the beginning of an array

Question 16

What do splice() and slice() have in common?

Answer 16

They both work in the middle of an array

Question 17

How is slice() different from pop(), push(), shift(), unshift(), and splice()?

Answer 17

It does not affect the existing array/string (usually)
It creates a new array/string (usually)

(Technically, you could splice from the existing array BACK TO the existing array, but it would remove all the non-sliced elements from the existing array)

Question 18

The methods slice() and splice() both use two numbers in the parentheses. What do they mean?

Answer 18

*For both slice() and splice(), the first number in parentheses is the index number where the work starts.

*for slice(), the second number is the index number AFTER the final element to be removed.

*for splice(), the second number is the total number of elements being removed.

Question 19

What’s a colloquial way to think of the ELSE IF command?

Answer 19

“If that’s not true, check this:”

or

“If that doesn’t match, try this:”

Question 20

What is this code?

for (var 1 = 0; i<=4; i++) {
//code to run goes here
}

Answer 20

a FOR loop