find all occurrences of a string in javascriptfind all occurrences of a string in javascript

Low voltage dc and ac high voltage in the same conduit, Using a comma instead of and when you have a subject with two verbs. How and why does electrometer measures the potential differences? When complete, you will still have 'test abc'! Find phrases used multiple times in string. 5 Answers Sorted by: 36 Try something like: var regexp = /abc/g; var foo = "abc1, abc2, abc3, zxy, abc4"; var match, matches = []; while ( (match = regexp.exec (foo)) != null) { matches.push (match.index); } console.log (matches); Share Follow answered Jul 29, 2010 at 18:56 cic 7,310 3 23 35 Imo this should be the top answer. String.prototype.indexOf () The indexOf () method of String values searches this string and returns the index of the first occurrence of the specified substring. Your function will use strstr() in a while loop to find the first match of str2 in str1. In some cases you might want to use that. It only takes a minute to sign up. What do multiple contact ratings on a relay represent? Approach 1: Using match () function: match () function used to search a string for a match against any regular expression. In this demo, i will show you how to create a pulse animation using css. You can get around this issue using regular expressions that are, I admit, somewhat more complex and as an upshot of that, a tad slower, too: The output is the same as the accepted answer, however, using the /cat/g expression on this string: Oops indeed, this probably isn't what you want. With Java 9, you can use the IntStream.iterate(seed, hasNext, next) method which returns a sequential ordered IntStream produced by application of the next function to an initial element seed, conditioned on satisfying the hasNext predicate. The tests RA and RB use recursion. If the regex does not include the g flag, the str.match()method will return the same result as RegExp.exec(). The result is the same as the native replaceAll in case of the first argument input is: Can a lightweight cyclist climb better than the heavier one by producing less power? Find the number of all specific substrings in a string, Method to generate a List containing permutation of an input string, Find all permutations of string using recursion. worked better for me than the previous answers. This used to be faster in some cases than using replaceAll and a regular expression, but that doesn't seem to be the case anymore in modern browsers. How to find occurrences of a string in string in C++? If regexp is a regex, then it must have the global (g) flag set, or a TypeError is thrown. The pattern can be a string or regExp. I could not find a completely right method in answers. But as here @sebastian-simon explained about, that can make secondary problems in case of more advanced uses. Is it unusual for a host country to inform a foreign politician about sensitive topics to be avoid in their speech? The original string is left unchanged. Are the NEMA 10-30 to 14-30 adapters with the extra ground wire valid/legal to use and still adhere to code? New! Regexp isn't the only way to replace multiple occurrences of a substring, far from it. Does adding new water to disinfected water clean that one as well? 1. Description The implementation of String.prototype.matchAll itself is very simple it simply calls the Symbol.matchAll method of the argument with the string as the first parameter (apart from the extra input validation that the regex is global). Not the answer you're looking for? "Hey @ronald and @tom where are we going this weekend". It only takes a minute to sign up. To learn more, see our tips on writing great answers. The task Given a string and a pattern, find the starting indices of all occurrences of the pattern in the string. I discourage from using replaceAll at this moment (2020). However I want to find the strings which start with "@". Results for Chrome. The implementation assumes that the caller will escape the string beforehand or will only pass strings that are without the characters in the table in Regular Expressions (MDN). We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. Without matchAll(), it's possible to use calls to regexp.exec() (and regexes with the g flag) in a loop to obtain all the matches: With matchAll() available, you can avoid the while loop and exec with g. Instead, you get an iterator to use with the more convenient forof, array spreading, or Array.from() constructs: matchAll will throw an exception if the g flag is missing. We have discussed the Naive pattern-searching algorithm in the previous post . Connect and share knowledge within a single location that is structured and easy to search. The global (g) in the regular expression instructs to search the whole string rather than just find the first occurrence: If there are no matches, it will return null: There is another solution provided by string.prototype.split() which splits the string and determine the count by using the length of the resulting array: The match() method retrieves the output of matching a string against a regex. Find all occurrences of substring in string. The compatibility considerations are easy to find on, well at first glance I didn't find anything mentioning older browsers and OLE implementations in legacy code. It's now supported in Chrome 85+, Edge 85+, Firefox 77+, Safari 13.1+. Are arguments that Reason is circular themselves circular and/or self refuting? Today 27.12.2019 I perform tests on macOS v10.13.6 (High Sierra) for the chosen solutions. OverflowAI: Where Community & AI Come Together, C find all occurrences of substring [closed], Behind the scenes with the folks building OverflowAI (Ep. I am trying to find all the occurences of "|" in a string. Your function will use strstr () in a while loop to find the first match of str2 in str1. Are modern compilers passing parameters in registers instead of on the stack? as shown here: But check Can I use or another compatibility table first to make sure the browsers you're targeting have added support for it first. occurrences of the pattern in the string. will return a list of the indices of yourString in which the | occur. If you feel that this question can be improved and possibly reopened, Not the answer you're looking for? console.log(theString.split("to").length - 1); How to Check If a String Contains Another Substring in JavaScript, How to Check Whether a String Matches a RegEx in JavaScript, How to Encode and Decode Strings with Base64 in JavaScript, How to Convert JavaScript String to be All Lowercase and Vice Versa, How to Replace All Occurrences of a String in JavaScript, How to Capitalize the First Letter in a String in JavaScript, How to Convert a Comma-Separated String into Array, How to Convert a String into a Date in JavaScript, How to Convert String to Number in JavaScript, How to Get the Last Characters of a String, How to Get the First Character of a String. The idea is to create a matcher to match the string for the specified character. The actual implementation comes from RegExp.prototype[@@matchAll](). How to replace all occurrences of a character in string? How to adjust the horizontal spacing of a table to get a good horizontal distribution? E.g., in case of any, This method is dangerous, do not use it. Connect and share knowledge within a single location that is structured and easy to search. The function is spelled wrong on the definition line. This post will discuss how to find indexes of all occurrences of a character in a string in Java. Approach 1 (Naive Approach) : A simple solution is to check all substrings of a given string one by one. Here's a string prototype function based on the accepted answer: If your find contains special characters then you need to escape them: These are the most common and readable methods. Warning! Find centralized, trusted content and collaborate around the technologies you use most. For example, given the The way I'd do this, is with a recursive function. Javascript function gfg () { let r = "Geeks For Geeks "; console.log ( The best answers are voted up and rise to the top, Not the answer you're looking for? It takes an optional starting position and returns the first occurrence of the specified substring at an index greater than or equal to the specified number. As pointed out in a comment here, this will not work if your omit variable contains place, as in: replaceAll("string", "s", "ss"), because it will always be able to replace another occurrence of the word. 18 Answers Sorted by: 209 var str = "I learned to play the Ukulele in Lebanon." var regex = /le/gi, result, indices = []; while ( (result = regex.exec (str)) ) { indices.push (result.index); } UPDATE I failed to spot in the original question that the search string needs to be a variable. IMHO, a regex that only replaces 'cat' conditionally (i.e., not part of a word), like so: My guess is, this meets your needs. If the replacement string contains the search keyword, then an infinite loop will occur. How do you understand the kWh that the power company charges you for? By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. The worst case complexity of the Naive algorithm is O (m (n-m+1)). Results for Chrome: RangeError: Maximum call stack size exceeded, I try to perform tests for 1M characters for other solutions, but E,F,G,H takes so much time that browser ask me to break script so I shrink test string to 275K characters. In the latest versions of most popular browsers, you can use replaceAll How to search for a string in a string in C#? For example, we can support IE7+ too, by not using Object.defineProperty() and using my old naive assignment method: And it should work well for basic uses on IE7+. OverflowAI: Where Community & AI Come Together, Find all the occurrences of a character in a string, Behind the scenes with the folks building OverflowAI (Ep. Be the first to rate this post. This has already been suggested or mentioned in 18 other answers, and in the comments under the question. c#; Share. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. For Node.js and compatibility with older/non-current browsers: Note: Don't use the following solution in performance critical code. How can I change elements in a matrix to a combination of other elements? The following example demonstrates how to use the indexOf () method efficiently, where the search for the next index starts from the previous index. For What Kinds Of Problems is Quantile Regression Useful? Are self-signed SSL certificates still allowed in 2023 for an intranet server running IIS? Like @Roland Illig said, your code has bug with "banana" because of you mutable your string length each time you use your substring function. How to display Latin Modern Math font correctly in Mathematica? Great! The split() method cuts a string into an ordered set of substrings, puts these substrings into an array, and returns an array. I don't think this will work, because startposition never changes - it'll loop for ever if there's a match. Watch a video course JavaScript - The Complete Guide (Beginner + Advanced) match () It stands for Knuth-Morris-Pratt, it's an algorithm that does text research aka looking for string into string. How to get the index of duplicates in a string. How to set, clear, and toggle a single bit? Not the answer you're looking for? Here we suggest two working solutions. Making statements based on opinion; back them up with references or personal experience. What is telling us about Paul in Acts 9:1? In this tutorial, we are going to learn about how to count the number of occurrences a particular string in a given string using JavaScript. suffix array, because. replacing tt italic with tt slanted at LaTeX level? If it's really long, you might consider some pre-processing for fast operation afterwards. rev2023.7.27.43548. All browser compatibility updates at a glance, Frequently asked questions about MDN Plus. On each iteration, increment the count for the current element if it exists or initialize the count to 1. index.js ": In response to Click Upvote's comment, you could simplify it even more: Note: Regular expressions contain special (meta) characters, and as such it is dangerous to blindly pass an argument in the find function above without pre-processing it to escape those characters. let count = (temp.match(/to/g) || []).length; 594), Stack Overflow at WeAreDevelopers World Congress in Berlin, Temporary policy: Generative AI (e.g., ChatGPT) is banned, Preview of Search and Question-Asking Powered by GenAI, C Trying to match the exact substring and nothing more. You can run tests on your machine HERE. Although, what I'm curious about is why the "new RegExp()" syntax gives that much of an improvement. 594), Stack Overflow at WeAreDevelopers World Congress in Berlin, Temporary policy: Generative AI (e.g., ChatGPT) is banned, Preview of Search and Question-Asking Powered by GenAI. This is a simple regex that avoids replacing parts of words in most cases. Enter your email address to subscribe to new posts. Could the Lightning's overwing fuel tanks be safely jettisoned in flight? Not knowing too much about how regular expressions work behind the scenes in terms of efficiency, I tended to lean toward the split and join implementation in the past without thinking about performance. let count = temp.match(/is/g); rev2023.7.27.43548. "Who you don't know their name" vs "Whose name you don't know", Heat capacity of (ideal) gases at constant pressure. To count the occurrences of each element in an array: Declare a variable that stores an empty object. matchAll internally makes a clone of the regexp so, unlike regexp.exec(), lastIndex does not change as the string is scanned. How would you count occurrences of a string (actually a char) within a string? Here we suggest two working solutions. In this tutorial, we are going to learn about how to count the number of occurrences a particular string in a given string using JavaScript. How to handle repondents mistakes in skip questions? In this case we need polyfill (forcing older browsers to support new features) (I think for a few years will be necessary). Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Code Review Stack Exchange is a question and answer site for peer programmer code reviews. There is another jsperf with variants on my recursive replace that go even faster (http://jsperf.com/replace-all-vs-split-join/12)! This page was last modified on Apr 5, 2023 by MDN contributors. How to initialize all members of an array to the same value? In this demo, i will show you how to create a snow fall animation using css and JavaScript. I couldn't find. Following is a simple example demonstrating usage of this: To get the indexes of all appearances of a character in a String, you can also use a regex. How to adjust the horizontal spacing of a table to get a good horizontal distribution? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Improve this question. Input is two strings, the first string being the long string and the second smaller string being the permuted string. C++11 introduced a standardized memory model. In the above code, we have passed regex /hello/g where g is the global flag which is used to get the array of all occurrences hello in the string instead of first occurrence. 2 Answers. Hint: Count the number of times each character occurs. It looks like currently it is the shortest one which does the question job: The tests were performed on Chrome 79.0, Safari 13.0.4 and Firefox 71.0 (64 bit). Making statements based on opinion; back them up with references or personal experience. Consider we have a string like this. is there a limit of speed cops can go on a high speed pursuit? javascript; algorithm; programming-challenge; or ask your own question. OverflowAI: Where Community & AI Come Together. You can then print the offset of that match. Now consider advancing one character through longString: you remove longString.charAt(i) and add longString.charAt(shortString.length + i). Now apply that to your search problem. When we do search for a string in a notepad/word file or browser or database, pattern-searching algorithms are used to show the search results. permutations_shortStrings[i] is a mouthful. Why do we allow discontinuous conduction mode (DCM)? How to Count String Occurrence in String You can count the string occurrence in a string by counting the number of times the string present in the string. How to create a string "replace all" function? Are arguments that Reason is circular themselves circular and/or self refuting. The pattern can be a string or a RegExp, and the replacement can be a string or a function called for each match. 37.1k 25 . What is the use of explicitly specifying if a function is recursive or not? Thus, the answer to the given example is . We can also use the split() method to count the number occurrences of a string. thanks. @NishargShah I do not remember what comments were on this answer 2 years ago but if you would like to edit this answer and credit yourself feel free. Another compelling reason for matchAll is the improved access to capture groups. That way, we can count the number of occurrences of that element in an array. Why do some ; have a space before them and others not? How long is the string we're talking about? The best answers are voted up and rise to the top, Not the answer you're looking for? This'll prove useful in perfecting this expression to meet your specific needs. This method accepts a separator and separates a string based on it. Examples text.find() only returns the first result, and then you need to set the new starting position based on that. Will reimplement the code. 594), Stack Overflow at WeAreDevelopers World Congress in Berlin, Find the starting indices of all occurrences of the pattern in the string - KMP algorithm follow-up, Find all occurrences of all permutations of a shorter string within a longer string, Find all starting indices in a string which are anagrams of a word, Find index of the nearest larger number of a number, Return the first recurring character in a string, Find the smallest distance between any two given words in a string, Check whether string of brackets are well-formed, Find all pairs of unique indices in a list such that the concatenation of the two words is a palindrome, Find indices of two numbers such that they add up to a target, Python program to find the substring with concatenation of all words, The Journey of an Electromagnetic Wave Exiting a Router. [duplicate], Find all substring's occurrences and locations, Behind the scenes with the folks building OverflowAI (Ep. But what if the browser is from before 2020? To learn more, see our tips on writing great answers. Do the 2.5th and 97.5th percentile of the theoretical sampling distribution of a statistic always contain the true population parameter? At the very least, store the result of. Now this is one hell of an in depth answer! To subscribe to this RSS feed, copy and paste this URL into your RSS reader. 594), Stack Overflow at WeAreDevelopers World Congress in Berlin, Temporary policy: Generative AI (e.g., ChatGPT) is banned, Preview of Search and Question-Asking Powered by GenAI. rev2023.7.27.43548. On my Chrome Windows8 machine, the regular expression based implementation is the fastest, with the split and join implementation being 53% slower. In this demo, we are going to learn about how to rotate an image continuously using the css animations. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Thanks for contributing an answer to Code Review Stack Exchange! Why is the expansion ratio of the nozzle of the 2nd stage larger than the expansion ratio of the nozzle of the 1st stage of a rocket? The second part is what gets replaced to, in your case empty string (""). Here the code to find string occurance in string with user defined Find function. How do I keep a party together when they have conflicting goals? Hint: In addition to counts of the characters, you might find it useful to have a count of the number of characters for which the difference is non-zero. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. :( I wish I could delete this. How to display Latin Modern Math font correctly in Mathematica? If regexp is not a RegExp object and does not have a Symbol.matchAll method, it is implicitly converted to a RegExp by using new RegExp(regexp, 'g'). Replace all occurrences of a string no matter how different it written. Are modern compilers passing parameters in registers instead of on the stack? I'd recommend reading some more on these pages. Loop it until number occurrences comes to 0, like this: This is the fastest version that doesn't use regular expressions. One of the solution can be provided by the match() function, which is used to generate all the occurrences of a string in an array. "If pattern is a string, only the first occurrence will be replaced. " Learn more about Stack Overflow the company, and our products. Javascript #include <stdio.h> #include <string.h> int countOccurrences (char *str, char *word) { char *p; char *a [300]; int index=0; p = strtok(str, " "); while (p != NULL) { a [index++]= (p); p = strtok(NULL, " "); } int c = 0; for (int i = 0; i < index; i++) if (strcmp(word , a [i])==0) { Could the Lightning's overwing fuel tanks be safely jettisoned in flight? Note: In general, extending the built-in prototypes in JavaScript is generally not recommended. It would be nice if this was also standardized as RegExp.escape(str), but alas, it does not exist: We could call escapeRegExp within our String.prototype.replaceAll implementation, however, I'm not sure how much this will affect the performance (potentially even for strings for which the escape is not needed, like all alphanumeric strings). 4 Answers. Algebraically why must a single square root be done on all terms rather than individually? Alaska mayor offers homeless free flight to Los Angeles, but is Los Angeles (or any city in California) allowed to reject them? rev2023.7.27.43548. Find a substring within a string in C#. How do I iterate over the words of a string? send a video file once and multiple users stream it? Sci fi story where a woman demonstrating a knife with a safety feature cuts herself when the safety is turned off. How to find the end point in a mesh line. To replace all occurrences of a string in Javascript, use the below methods Javascript string replace method with regular expression Javascript split and join method Javascript indexOf method Take a look at the below example of Javascript Replace () method The Journey of an Electromagnetic Wave Exiting a Router, Previous owner used an Excessive number of wall anchors, Effect of temperature on Forcefield parameters in classical molecular dynamics simulations. There are basically two ways to do this as suggested by the other answers on this page. Why is an arrow pointing through a glass of water only flipped vertically but not horizontally? You can then print the offset of that match. console.log(count); let temp = "Welcome to W3Docs"; 594), Stack Overflow at WeAreDevelopers World Congress in Berlin, Temporary policy: Generative AI (e.g., ChatGPT) is banned, Preview of Search and Question-Asking Powered by GenAI, Fastest method to replace all instances of a character in a string, JavaScript - Replace all commas in a string, JavaScript .replace only replaces first Match. The strstr () function shall locate the first occurrence in the string pointed to by s1 of the sequence of bytes (excluding the terminating null byte) in the string pointed to by s2. 0. Here, str.match (re); gives ["o", "o"]. However I want to find the strings which start with "@". As noted in the comment below by @ThomasLeduc and others, there could be an issue with the regular expression-based implementation if search contains certain characters which are reserved as special characters in regular expressions. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. : In fact, my suggested option is a little optimistic. Example: Counting occurrence of Geeks in "GeeksforGeeks" using the "match ()" function. The matchAll() method returns an iterator of all results matching a string against a regular expression, including capturing groups. Best solution for undersized wire/breaker? Why the blank line before the closing }? Can a judge or prosecutor be compelled to testify in a criminal trial in which they officiated? @SethCarnegie .. If you just need the index of the characters last appearance in a string, use the lastIndexOf() method. The replace () method in javascript looks for a pattern and replaces some or all of its occurrences with a replacement (string). Perhaps (at risk of being voted down) that can be combined for a slightly more efficient but less readable form: This can be particularly useful when looking for duplicate strings. You'll continue the search at the first character after the match. If I allow permissions to an application using UAC in Windows, can it hack my personal files or data? The actual implementation comes from RegExp.prototype [@@matchAll] (). The match() method accepts the regex as an argument and it returns the array of matched values. E.g. Meaning the regular expressions are twice as fast for the lorem ipsum input I used. BCD tables only load in the browser with JavaScript enabled. KMP) can allow you to skip more than one character at a time, but the one I've outlined already gets you down to linear time (subject to certain assumptions) so beyond that it's just a case of improving the constant factor. Replace " ' " with " '' " in JavaScript. You'll stop the loop when strstr() no longer finds a match (signalled by strstr() returning NULL). However, this means that unlike using regexp.exec() in a loop, you can't mutate lastIndex to make the regex advance or rewind. The Journey of an Electromagnetic Wave Exiting a Router. In response to comment "what's if 'abc' is passed as a variable? The problem can be solved in \$O(m+n)\$ time. How can I find the shortest path visiting all nodes in a connected graph as MILP? Try it Syntax Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. String.prototype.replaceAll() not working, Remove a semicolon in a string by JavaScript.