In JavaScript, a string is a sequence of characters stored as a single data type. Strings are widely used for representing text and are essential for working with textual data in JavaScript.
Definition:
A string in JavaScript is a primitive data type that represents a sequence of characters enclosed within single (
') or double (") quotes. For example:
let greeting = "Hello, world!";
let name = 'John Doe';
Characteristics:
Immutable: Strings in JavaScript are immutable, meaning once a string is created, its value cannot be changed. However, you can create a new string based on the original string’s value.
Unicode Support: JavaScript strings support Unicode characters, allowing you to work with characters from various languages and symbol sets.
Escape Sequences: Strings can include special characters and escape sequences, such as
\nfor newline,\tfor tab,\\for backslash, etc.
String Methods:
JavaScript provides a variety of built-in methods to manipulate and work with strings effectively. Some common string methods include:
length: Returns the length of the string.charAt(index): Returns the character at the specified index.concat(str1, str2, ...): Concatenates one or more strings with the original string.indexOf(substring): Returns the index of the first occurrence of the specified substring within the string.substring(startIndex, endIndex): Returns a new string containing characters fromstartIndexup to but not includingendIndex.slice(startIndex, endIndex): Returns a portion of the string, starting fromstartIndexup to but not includingendIndex.toUpperCase(): Converts the string to uppercase.toLowerCase(): Converts the string to lowercase.split(separator): Splits the string into an array of substrings based on the specified separator.
Example:
let str = "Hello, world!";
console.log(str.length);
// Output: 13
console.log(str.charAt(0));
// Output: H
console.log(str.indexOf("world"));
// Output: 7
console.log(str.toUpperCase());
// Output: HELLO, WORLD!
console.log(str.split(", "));
// Output: ["Hello", "world!"]
