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Practice

What are Data Types?

Data types refer to the Type of data such as text, numbers, true/false values, etc.


1. Number​

Represents numeric values, including integers, floating-point numbers, and natural numbers.

Example:

Number Data Type
let age = 16;
let height = 5.9;

2. String​

Strings represent textual information. Any letters, words, or sentences enclosed in quotes (' ', " ") are considered strings.

Example:

String Data Type
let name = 'John';
let message = 'Hello, there!';

3. Boolean​

The Boolean data type can only hold one of two values: true or false. It's like turning a switch on and off.

Example:

Boolean Data Type
let isStudent = true;
let hasDriverLicense = false;

4. Object​

Objects are used to store multiple values in a single variable. For example, a student object can hold name, age, and grade information.

Example:

Object Data Type
let student = {
  name: 'John',
  age: 16,
  grade: 'Sophomore',
};

5. Array​

Arrays are used to store multiple values of the same type in a single variable.

Example:

Array Data Type
let fruits = ['Apple', 'Banana', 'Grapes'];

6. Other Data Types​

  • null

null is a special value that represents 'no value'. It is used to explicitly indicate that a variable should have no value.

Example:

null Data Type
let emptyValue = null;

  • undefined

undefined is used to indicate that a variable has been declared but has not yet been assigned a value. It means 'not defined'. When a variable is declared without initialization, JavaScript assigns it a value of undefined.

Example:

undefined Data Type
let notDefinedYet;
console.log(notDefinedYet); // Output: undefined
  • null and undefined both represent the concept of 'no value', but they are used in different contexts and have different meanings. null is used when you want to explicitly indicate that a variable has no value, whereas undefined indicates that a variable has not been initialized or a value has not been assigned where it was expected.

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