JavaScript(2)---Variables

Variables

In programming, a variable is a container for a value. You can think of variables as little containers for information that live in a computer’s memory. Information stored in variables, such as a username, account number, or even personalized greeting can then be found in memory.

There are a few general rules for naming variables:

• Variable names cannot start with numbers.

• Variable names are case sensitive, so myName and myname would be different variables. It is bad practice to create two variables that have the same name using different cases.

• Variable names cannot be the same as keywords.

1. The var, short for variable, is a JavaScript keyword that creates, or declares, a new variable.
2. The let keyword signals that the variable can be reassigned a different value. 
3. The way you declare a const variable and assign a value to it follows the same structure as let and var. A const variable cannot be reassigned because it is constant. 

Mathematical work and symbols:

levelUp += 5;

powerLevel -= 100;

multiplyMe *= 11;

quarterMe /= 4;

• Other mathematical assignment operators include the increment operator (++) and decrement operator (--).

EX: increase the value of gainedDollar.

gainedDollar++;

String Concatenation with Variables

EX: Use console.log() to print 'My favorite animal: ANIMAL' to the console. Use string concatenation so that ANIMAL is replaced with the value in your favoriteAnimal variable.

let favoriteAnimal = "giraffe";

console.log("My favorite animal: " + favoriteAnimal);

String Interpolation

A template literal is wrapped by backticks ` (this key is usually located on the top of your keyboard, left of the 1 key).

Inside the template literal, you’ll see a placeholder, ${myPet}. The value of myPet is inserted into the template literal.

When we interpolate `I own a pet ${myPet}.`, the output we print is the string: 'I own a pet armadillo.'

What I learned today...

What I'll be doing tomorrow...

 I'll be learning the CONDITIONAL STATEMENTS JavaScript.