#6 Javascript Strings | Javascript Hindi Course For Beginners ( 2023 )

Basics of string

// Double Qoutes -> " "
let name = "Anshu Raj";
// Single Qoutes -> ' ';
let channel = 'Do Some Coding';
// Template  Literals -> ' ';
let newone = `This is called template literals`;

// these are three ways to assgin strings

Escape Characters

 let message = 'Don't do this';
 // above line will throw string error
// as we are using single qoutes inside string

// how to fix this issue

// 1. First Way
let message = "Don't do this";
// if are using single qoutes inside string then use double qoutes outside
let message = 'Don"t do this';
// if are using double qoutes inside string then use single qoutes outside

// 2 . Second Way
let message = 'Don\'t do this';
// use \ after single qoutes that is inside it will fix it
let message = "Don\"t do this";
// use \ after single qoutes that is inside it will fix it

// for creating new line inside string ->  " \n "
const message = "This is best course on entire youtube. \n I am providing Pratice Questions too "
// for creating line break inside string ->  " \r "
const message = "This is best course on entire youtube. \r I am providing Pratice Questions too "
// for creating space inside string => " \t "
const message = " Subscribe \t this channel ";

// Template Literals helps you to run javascript code inside string

const name = "Anshu Raj"

const message = `Anshu Raj is Developer.`
const message2 = `${name} is Developer.` // new method
const message3 =  name + 'is Developer.' // old method

String Methods

const channel = "Do Some Coding";

// Change String to Upper Case

channel.toUpperCase(); //  -> "DO SOME CODING"

// Change String to Lower Case

channel.toLowerCase(); //  -> "do some coding"

// Trim Text from String
const greeting = "   Hello world!   ";

console.log(greeting);
// Expected output: "   Hello world!   ";

console.log(greeting.trim());
// Expected output: "Hello world!";

// Get length of string

channel.length; //  -> 14

// Get character at index

channel.charAt(0); //  -> "D"

// Get character code at index

channel.charCodeAt(0); //  -> 68

// Match o in string

channel.match(/o/g); //  -> ["o", "o"]

// Replace Coding with Learning

channel.replace("Coding", "Learning"); //  -> "Do Some Learning"

// Split string into array

channel.split(" "); //  -> ["Do", "Some", "Coding"]

// Continate string "Do Some Coding" with " is fun"

channel.concat(" is fun"); //  -> "Do Some Coding is fun"

// Get Sub String from index 3 to 7

channel.substring(3, 7); //  -> "Some"

//  Check channel start with "Do"

channel.startsWith("Do"); //  -> true

// Check channel end with "ing"

channel.endsWith("ing"); //  -> true

// Check channel includes "Some"

channel.includes("Some"); //  -> true

// Get index of "Some"

channel.indexOf("Some"); //  -> 3

// Get last index of "o"

channel.lastIndexOf("o"); //  -> 11

// Search string
const paragraph =
  "The quick brown fox jumps over the lazy dog. If the dog barked, was it really lazy?";

// Any character that is not a word character or whitespace
const regex = /\bDog\b/gi;

paragraph.search(regex); //  -> 40

1. Try to replace “dog” with “cat” from Sample String → “ he quick brown fox jumps over the lazy dog. If the dog barked, was it really lazy?”

2. Write a function to convert string to lowercase;

3. Check “Fox” is includes . Sample String → “ he quick brown fox jumps over the lazy dog. If the dog barked, was it really lazy?”

4. Check String end with “?” . Sample String → “ he quick brown fox jumps over the lazy dog. If the dog barked, was it really lazy?”

5. Extract Amount from string → “ I bought car at ₹ 550000 “