README.md

String In JavaScript

Length of a String

let firstName = "Vaishali";
console.log(firstName.length);

Access String Element

console.log(firstName.charAt(2)); // i
console.log(firstName[2]); // i
console.log(firstName.charCodeAt(2)); // 115 (Ascii Code)

Check Presence of Character

console.log(firstName.includes("r")); // false (& if present it return true)
console.log(firstName.indexOf("i")); // 2 (& if not present it return -1)
console.log(firstName.lastIndexOf("i")); // 7 

Compare Two Strings

let anotherName = "Vishal";
console.log(firstName.localeCompare(anotherName)); // -1 (& if strings are equal it return 0)

Replace Substring

const str = "Vishal is Best Frontend Developer. Vishal is Best Developer. ";
console.log(str.replace("Vishal", "Sujit")); // "Sujit is Best Frontend Developer. Vishal is Best Developer. "
console.log(str.replaceAll("Vishal", "Sujit")); // "Sujit is Best Frontend Developer. Sujit is Best Developer. "

Substring of a String

console.log(str.substring(6, 30)); 
console.log(str.slice(-10, -1));

Split and Join

console.log(str.split(""));
const subString = str.split(" ");
console.log(subString.join(" "));

String Start and End

console.log(str.startsWith("Vishal")); // true
console.log(str.endsWith("Developer")); // true

Trim and Case Conversion

const trimStr = str.trim();
const trimStrStart = str.trimStart();
const trimStrEnd = str.trimEnd();
console.log(trimStr, trimStr.length);
console.log(str.toLowerCase());
console.log(str.toUpperCase());

Convert Number and Object to String

const num = 123;
console.log(num, num.toString());

const obj = {
    name: "Vishal",
    course: "DSA with Vishal"
};
console.log(obj, JSON.stringify(obj));

Concatenate Strings

const lastName = "Rajput";
console.log(firstName + lastName);
console.log(`${firstName} ${lastName} is a Best Developer`);
console.log(firstName.concat(lastName, " is a", " Best"));

Practice Questions

• Find the Index of the First Occurrence in a String
• Reverse String
• Valid Anagram
• Longest Common Prefix
• Merge Strings Alternately
• Length of Last Word
• Valid Palindrome
• String Compression
• Reverse Words in a String
• Reverse Vowels of a String
• Rotate String