Lecture 5: Javascript: Basics

Question 1

Variables

Answer 1

let message = ‘Welcome’

Question 2

Variable declaration

Answer 2

Let: for true variables you might want to re-assign
Const: for variables that are not re-assigned
Var: old, replaced by ‘let’.

Question 3

Types

Answer 3

No Types are declared, JS dynamically assigns data types.

Question 4

Variable names

Answer 4

cannot start with numbers, cannot start with keywords and ARE case-sensitive

Question 5

Number

Answer 5

Numeric types(64 float)

Question 6

String

Answer 6

text

Question 7

Boolean

Answer 7

true/false

Question 8

Null

Answer 8

lack of value

Question 9

Undefined

Answer 9

never defined

Question 10

Strict Equality

Answer 10

===

Question 11

If statement

Answer 11

if(i === 6){
Do Something
}
else{
Do something else
}

Question 12

What is True or False?
All evaluated as false:

Answer 12

False, null, undefined, “”, 0, NaN

Question 13

What is True or False? All evaluated as True

Answer 13

True, “hello”, “false”, 1, -1

Question 14

Arrays

Answer 14

A collection of data
Zero-based indexing
Example:
Let students = [“Alex”, “Ralph”, “Michael”, “Eric”];

Question 15

for loop

Answer 15

Classic for loop. Counting things & operating via indices
for( let i = 0; i <students.length; i++){
Let name = students[i];
console.log(“Hi “ + name + “! You are at spot “ + i);}

Question 16

for of loop

Answer 16

for(let name of students){
console.log(“Hi “ + name + “! );}