How to get the string between curly braces using JavaScript's regular expression?-JS Tutorial-php.cn

Home

Web Front-end

JS Tutorial

How to get the string between curly braces using JavaScript's regular expression?

PHPz

Aug 23, 2023 am 08:41 AM

How to get the string between curly braces using JavaScripts regular expression?

We can create a regular expression so that it can find all substrings between curly braces. After that, we can use the exec() or match() method to extract the matching substring.

In this tutorial, we will learn to use JavaScript’s regular expressions to get the string between curly braces. For example, if we have a string like 'This is a {string} with {curly} braces, we need to extract all substrings that reside between the curly braces. .

Use the exec() method and regular expressions to get the string between curly braces

The exec() method is usually used with regular expressions to find matching substrings. It returns all matching results in array format, or null if no matching is found.

grammar

Users can follow the syntax below to use the exec() method with the regular expression to get all substrings between the curly braces.

var regex = /{([^}]+)}/g;
while (match = regex.exec(originalStr)) {
   results.push(match[1]);
}

In the above syntax, we created a regular expression to find the substring between curly braces. We then loop through the matches array and get all matching occurrences.

The Chinese translation of

Example

is:

Example

The 'originalStr' variable contains the string with curly braces in the example below. The regex.exec() method returns a two-dimensional array of all matching substrings. Each element of the array is an array containing two strings. The first element is the string with curly braces and the second element is the string without curly braces that we want to extract.

In the output, the user can observe that it shows the "Developers" and "JavaScript" substrings since they are both between curly braces.

<html>
<body>
   <h3 id="Using-the-i-regular-expression-and-exec-method-i-to-get-string-between-curly-braces-in-JavaScript">Using the <i> regular expression and exec() method </i> to get string between curly braces in JavaScript</h3>
   <div id = "demo"> </div>
   <script>
      let output = document.getElementById("demo");
      function getStringBetweenBraces() {
         var originalStr = "Hello {Developers}! Let's develop {JavaScript} code!";
         var found = [];
         var regex = /{([^}]+)}/g;
         var results = [];
         let match;
         while (match = regex.exec(originalStr)) {
            results.push(match[1]);
         }
         output.innerHTML = "The original string is " + originalStr + "<br>";
         output.innerHTML += "The substrings between curly braces are " + results + "<br>";
      }
      getStringBetweenBraces();
   </script>
</body>
</html>

Use the match() method and regular expressions to get the string between curly brackets

The match() method also returns all matching occurrences in the string in array format.

grammar

Users can use the match() method and regular expressions according to the following syntax to get the string between curly braces

let results = originalStr.match(/{([^}]+)}/g);

In the above syntax, originalStr is a string with curly braces, and we pass the regular expression as the parameter of the match() method.

The Chinese translation of

Example

is:

Example

In the following example, the match() method returns an array of strings with curly braces. However, it does not return the string after the curly braces are removed. Users can use the subStr() or substring() method to remove curly braces from the returned results.

<html>
<body>
   <h3 id="Using-the-i-regular-expression-and-match-method-i-to-get-string-between-curly-braces-in-JavaScript">Using the <i> regular expression and match() method </i> to get string between curly braces in JavaScript</h3>
   <div id = "demo"> </div>
   <script>
      let output = document.getElementById("demo");
      function getStringBetweenBraces() {
         var originalStr = "This is {sample} string! This is {original} string!";
         let results = originalStr.match(/{([^}]+)}/g); 
         output.innerHTML = "The original string is " + originalStr + "<br>";
         output.innerHTML += "The substrings between curly braces are " + results + "<br>";
      }
      getStringBetweenBraces();
   </script>
</body>
</html>

Use a for loop to get the string between curly brackets

We can also extract all substrings between the curly braces by iterating the string using a for loop. We can keep track of the starting and ending index of the curly braces. We can then extract the substring from the original string using the substring() method.

grammar

Users can use the for loop according to the following syntax to extract the substring between curly braces.

for ( ) {
   if (str[i] == "{")
   start = i;
   if (str[i] == "}") {
      end = i;
      let bracesString = str.substring(start + 1, end);
   }
}

In the above syntax, we keep track of the starting and ending index of the curly braces and extract the string using the substring() method.

step

Step 1 - Use a for loop to traverse the string.

Step 2 - If the character with index 'I' in the string is equal to '{', store the value of the index in the start variable.

Step 3 - If the character with index 'I' in the string is equal to '}', store the value of the index in the end variable.

Step 3.1 − Use the substring() method to get the substring between the ‘start 1’ index after the ‘end’ index.

Step 3.2 - Push the resulting substring into an array.

The Chinese translation of

Example

is:

Example

In the example below, we followed the above steps to extract the string between the curly braces using a for loop. However, this method does not work for extracting strings between nested curly braces.

<html>
<body>
   <h3 id="Using-the-i-for-loop-i-to-get-string-between-curly-braces-in-JavaScript">Using the <i> for loop </i> to get string between curly braces in JavaScript</h3>
   <div id = "demo"> </div>
   <script>
      let output = document.getElementById("demo");
      function getStringBetweenBraces() {
         var str = "Hello {Users}! Welcome to {Website}!";
         var start = 0;
         var end = 0;
         let results = [];
         for (var i = 0; i < str.length; i++) {
            if (str[i] == "{") {
               start = i;
            }
            if (str[i] == "}") {
               end = i;
               let bracesString = str.substring(start + 1, end);
               results.push(bracesString);
            }
         }
         output.innerHTML = "The original string is " + str + "<br>";
         output.innerHTML += "The substrings between curly braces are " + results + "<br>";
      }
      getStringBetweenBraces();
   </script>
</body>
</html>

In this tutorial we learned how to extract the string between curly braces using regular expressions. In the first method, we used the exec() method with a regular expression; in the second method, we used the match() method with a regular expression.

In the third method, we use a for loop instead of a regular expression.

The above is the detailed content of How to get the string between curly braces using JavaScript's regular expression?. For more information, please follow other related articles on the PHP Chinese website!

Statement

This article is reproduced at:tutorialspoint. If there is any infringement, please contact admin@php.cn delete

Replace String Characters in JavaScriptMar 11, 2025 am 12:07 AM

Detailed explanation of JavaScript string replacement method and FAQ This article will explore two ways to replace string characters in JavaScript: internal JavaScript code and internal HTML for web pages. Replace string inside JavaScript code The most direct way is to use the replace() method: str = str.replace("find","replace"); This method replaces only the first match. To replace all matches, use a regular expression and add the global flag g: str = str.replace(/fi

8 Stunning jQuery Page Layout PluginsMar 06, 2025 am 12:48 AM

Leverage jQuery for Effortless Web Page Layouts: 8 Essential Plugins jQuery simplifies web page layout significantly. This article highlights eight powerful jQuery plugins that streamline the process, particularly useful for manual website creation

Build Your Own AJAX Web ApplicationsMar 09, 2025 am 12:11 AM

So here you are, ready to learn all about this thing called AJAX. But, what exactly is it? The term AJAX refers to a loose grouping of technologies that are used to create dynamic, interactive web content. The term AJAX, originally coined by Jesse J

10 Mobile Cheat Sheets for Mobile DevelopmentMar 05, 2025 am 12:43 AM

This post compiles helpful cheat sheets, reference guides, quick recipes, and code snippets for Android, Blackberry, and iPhone app development. No developer should be without them! Touch Gesture Reference Guide (PDF) A valuable resource for desig

Improve Your jQuery Knowledge with the Source ViewerMar 05, 2025 am 12:54 AM

jQuery is a great JavaScript framework. However, as with any library, sometimes it’s necessary to get under the hood to discover what’s going on. Perhaps it’s because you’re tracing a bug or are just curious about how jQuery achieves a particular UI

10 jQuery Fun and Games PluginsMar 08, 2025 am 12:42 AM

10 fun jQuery game plugins to make your website more attractive and enhance user stickiness! While Flash is still the best software for developing casual web games, jQuery can also create surprising effects, and while not comparable to pure action Flash games, in some cases you can also have unexpected fun in your browser. jQuery tic toe game The "Hello world" of game programming now has a jQuery version. Source code jQuery Crazy Word Composition Game This is a fill-in-the-blank game, and it can produce some weird results due to not knowing the context of the word. Source code jQuery mine sweeping game

How do I create and publish my own JavaScript libraries?Mar 18, 2025 pm 03:12 PM

Article discusses creating, publishing, and maintaining JavaScript libraries, focusing on planning, development, testing, documentation, and promotion strategies.

jQuery Parallax Tutorial - Animated Header BackgroundMar 08, 2025 am 12:39 AM

This tutorial demonstrates how to create a captivating parallax background effect using jQuery. We'll build a header banner with layered images that create a stunning visual depth. The updated plugin works with jQuery 1.6.4 and later. Download the

See all articles