문자열 함수

자바스크립트에서 문자열은 텍스트를 표현하는 데 사용되는 연속된 문자이다. 문자열은 작은따옴표 또는 큰따옴표로 묶는다.

다음은 자바스크립트에서 문자열을 만드는 방법의 예이다.

let message = "Hello, World!";

 

자바스크립트는 문자열을 조작하는 데 사용할 수 있는 다음과 같은 많은 내장 메서드를 제공한다:

• length: returns the number of characters in a string
• toUpperCase(): returns the string in uppercase
• toLowerCase(): returns the string in lowercase
• indexOf(substring): returns the index of the first occurrence of the substring in the string
• lastIndexOf(substring): returns the index of the last occurrence of the substring in the string
• slice(start, end): returns a new string that is a substring of the original string
• substring(start, end): returns a new string that is a substring of the original string
• substr(start, length): returns a new string that is a substring of the original string
• replace(oldValue, newValue): replaces all occurrences of the old value with the new value in the string
• trim(): removes whitespaces from the beginning and end of the string
• split(separator): splits the string into an array of substrings using the separator
• concat(string1,string2,..): joins two or more strings together

let message = "Hello, World!";
console.log(message.length); // Output: 13
console.log(message.toUpperCase()); // Output: "HELLO, WORLD!"
console.log(message.toLowerCase()); // Output: "hello, world!"
console.log(message.indexOf("World")); // Output: 7
console.log(message.slice(7, 12)); // Output: "World"
console.log(message.replace("World", "Friend")); // Output: "Hello, Friend!"
console.log(message.trim()); // Output: "Hello, World!"
console.log(message.split(",")); // Output: ["Hello", " World!"]
console.log(message.concat(" How are you?")); // Output: "Hello, World! How are you?"
console.log(message.startsWith("Hello"));  // Output: true
console.log(message.endsWith("World!"));   // Output: true