What Is a Regular Expression?
A regular expression is a sequence of characters that forms a search pattern.
When you search for data in a text, you can use this search pattern to describe what you are searching for.
A regular expression can be a single character, or a more complicated pattern.
Regular expressions can be used to perform all types of text search and text replace operations.
Syntax
/pattern/modifiers;Example
var patt = /world/i;Example explained:
/world/i is a regular expression.
world is a pattern (to be used in a search).
i is a modifier (modifies the search to be case-insensitive).
Regular Expression을 사용한 문자열 replace() 예제
Example
Use a case insensitive regular expression to replace Microsoft with W3Schools in a string:
var str = "Visit Microsoft!";
var res = str.replace(/microsoft/i, "Apple");The result in res will be:
Visit Apple!
<!DOCTYPE html>
<html>
<body>
<h2>JavaScript Regular Expressions</h2>
<p>Replace "microsoft" with "Apple" in the paragraph below:</p>
<button onclick="myFunction()">Try it</button>
<p id="demo">Please visit Microsoft and Microsoft !</p>
<script>
function myFunction() {
var str = document.getElementById("demo").innerHTML;
var txt = str.replace(/microsoft/i,"Apple");
document.getElementById("demo").innerHTML = txt;
}
</script>
</body>
</html>
참고자료 : https://www.w3schools.com/js/js_regexp.asp
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