Question mark in regex. Question marks followed by non-digits are left unchanged.
Question mark in regex *?) matches any character (. and needs no escaping. asked Oct 28, 2011 at 21:56. Then replace it with: That is so good isn't it? Yes it is I . Add a question mark at the end of quantifier will enable lazy match. Learn how to use regex to match and validate question mark symbols '?' in text. I have searched but I didn't find the right way to do it. So your regex probably The Question Mark (?) In regex, the meta character “?” makes the preceding character optional. Because of the question mark quantifier, this is okay for the regex engine. However, if a quantifier is followed by a question mark, then it becomes lazy, and instead As pointed out by user laalto, ? is a meta-character in regex. C# Regex is matching too much. The Regex engine is first expanding . If we use a greedy match of [a-z]+c (+ standing for 1+ repetitions or {1,}): [a-z]+ would match acac and fail at 1 then we would try to match the c, but fail at 1; now we start backtracking, and successfully match aca and c; If we make this lazy ([a-z]+?c), we will get both a different response (in this case) and be more In regexes, the question mark is an operator meaning one or none. As the documentation puts it:. How to exclude question mark from a string? 1. the F* would be a great addition to the pattern. Match will only return the first match it finds. But you need it to act as a literal in order to modify the ? within the regex. It is somewhat possible the author of this code could have used word boundaries instead ( \b ). regex match literal before question mark. 3. I Question mark in regex not working as expected. About question mark in regular expression. conf. the first time when awk reads your program, and the second time when it goes to match the string on the lefthand side of the operator with the pattern on the right. Repetition operators are special meta characters: ? (question mark), * (asterisk), and + (plus sign). See examples, syntax, and how to control greediness and alternatives (. string sentence = "\"This is the end?\""; The matches array contains two kinds of matches, the whole matched string, and your embraced patterns. Therefore, we have to escape it: s/question\?/reply?/g Note that it isn't special in strings. For input "does this string contain? the input" and literal Second, the escaped apostrophe. 170k 37 37 gold badges 306 306 silver badges 295 295 bronze badges. The remaining string is So what does it mean when we put a question mark in front of a character? regex; Share. How do I accomplish this? regex; apache; mod-rewrite; Share. You may be confusing regular expressions with shell globs. About; Products OverflowAI; Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI Python regex. But I managed to make it work by the following: grep [?]{3} * That is, I enclosed the question mark in character class brackets ( [and ]), which made the special meaning inactive. little confusing regex in java. ]+ If you meant to make the xmln and the xsi tags optional your regex should look like this Javascript Regex Split Words that ends with dot, exclamation, question mark, comma and on whitespace 3 Split string by period but not if whitespace after period Java regex question. An eg : I didn't have luck with backslash escaping, under windows grep. In grep, ? matches a literal question-mark character, and \? denotes zero or one occurrence of whatever precedes it. The {3} part is not relevant to the question, I used it to find 3 consecutive question marks. Question mark in regex not working as expected. In fact, F* and F? could sortta'kinda mean the same thing, and give me more room on the matching criteria. It When a string is interpolated as a regex, it isn't matched literally, but interpreted as a regex. The question mark can be combined with other regex features to create more complex patterns. Ask questions, find answers and collaborate at work with Stack Overflow for Teams. . P. Ensuring there's at least one question mark in the string. This is indeed a superior answer to what I had originally conceived. This symbol matches zero or one instance of the preceding character/group. I've tried the regex in several online regex testers and the captures appear to work, but there must be something about Nginx locations that I'm not understanding. I would like to get all my sentences back that have a question mark. Follow asked May 4, 2009 at 22:32. Bart Kiers. Could someone give me a regex that would work? (java) If it's possible then i would like to return the bold in the next example: I think you can try this regex: \s! You simply need to match two chars: space(\s) and exclamation mark(!). Also: You're using a basic regular expression (no -r or -E option), so ? is not a special char. I answered "How to check for a question mark in PHP string?", because the best answer to "How to check for a question mark in PHP string using regex?" is simply "Don't". How to use question marks as a normal char in @WendiT It's an X/Y question. For this I used the below regex, but its not working. Note: there will be various characters inbetween that I would like to capture also e. (This is in contrast to bare +, which means "one or more — and preferably as many as possible". Regular expressions with question mark. Modified 8 years, 2 months ago. E. Regular expression that works on dots. Hot Network Questions Integral not italic dx when and e is in the integral, why? A superhuman character only damaged by a nuclear blast’s fireball. Python regex with question mark literal. Altogether, the regex first checks if there is a question mark somewhere in the string to be matched. You'll get a match on any Learn how to use the question mark ? metacharacter to specify 0 or 1 occurrences of a pattern in regular expressions. 12. Firstly, some ground rules: `?` is not a special character in Java `?` is a reserved character in regex This entails: String test = "?"; // Valid statement in java, but illegal when used as a regex String test = "\?"; // Illegal use of escape character Why is the I don't think you've answered jonrsharpe's questions. and up to and including the ?. Ask Question Asked 8 years, 2 months ago. In multi-line strings this is different to the more familiar ^ and $, which match the beginning of a line and the end of a line. \netc This link helps What is the regex to find a single line of text preceding a question mark? example text: now"? How to escape backslash and question mark characters using rlike in Hive. But it can be just letters, as in most names. 2. I'm not good with regex, i just know a bit of what can be done. The greedy subpattern . Exercise 8: The pipe and the question mark Exercise 9: This or that Exercise 10: The question mark and its two meanings. Stack Exchange Network. This is useful to build complex regexes, e. regex question mark in javascript. com. In regular expression syntax . In the regex the question mark is considered a 'once or not at all'. These repetition characters are used to specify how many times a sub Quantifier in RegEx. ; In the replacement string, which is not a regex, do not escape . Question mark in regular expression matching is not working. You can get a look at the context HERE Well duh again, I'm going to have to So, Cisco's regex allows the question mark character. I tried adding uFFFD, xFFFD, EF BF BD, ï ¿ ½ formats to detect this unknown symbol but it did not work. I have found something which is very difficult to understand for me. Hot Network Questions Happy 2025! This math equation is finally true. Regex group doesn't match with "?" even if it should. Note that your regex contains non-word special chars that you need to quote before using them in the actual pattern. JavaScript Regex not detecting. Match method gets no success. You probably want to use Matches:. Your example could make sense either way around, but I suspect you have one of the dialects where ? is a literal and \? is the optional symbol. The empty space ' ' does not match the regex so the second part of the regex [cde] does not match. Let's see what's happening here. Regular expressions are teeming with quantifiers, each holding its own unique functionality. And, on regex, character ? has special meaning. Regex should accept multiple dots but don't. regex pattern to find full stop, exclamation mark or question mark in Java. You must work around that. How can I use mod_rewrite to remove everything after the ? (question mark) in a URL? 0. I have a feed in Yahoo Pipes and want to match everything after a question mark. I am really confused by studying this regex. I got a big file with all my email activity over the last 5 years. Regex - Why does the question mark behave like this? Hot Network Questions Best way to design a PCB for frequent component switching? Looking for a letter from H. For instance, if you expect the user to type in “color” or “behavior”, but you’re not Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company The regex will only match if the capturing group does not match. Java remove all Exclamation point. And of course, {1} is pure clutter. hostname + ')') Skip to main content. Regex for matching a pattern at the end of a URL. They can help you to extract exact information from a bigger match (which can also be named), they let you rematch a previous matched group, and can be used for substitutions. But it’s not matched more often. Is it possible to add this special unknown character to regex in c#? What is the correct unicode format to replace this unknown symbol? I am trying to define a pattern to match text with a question mark (?) inside it. I've manage to set everything up and the rules is working as expected. Java regex exact match with question mark and word boundary. Need a clue with Java regex. In this article let’s understand how we can create a regex for question mark and how regex can be matched for question mark values. For example, the I want to retrieve "the string between last slash and question mark (if exists)" i. Question Mark is represented by ? and can be keyed in using the keyboard using the SHIFT + ? in most computers. I mean, I would like a RewriteRule to grab both urls with OR without question mark . One such quantifier is the question mark?. Skip to main content. But why doesn't it work?. ) at the end of a sentence. , for the above examples, I want to retrieve "example". Could someone please explain me why its not working. If you were using egrep (aka grep -E), then answers indicating that ? is a zero-or-one-of-previous-entity regex metacharacter would be correct. \? Now just to match everything that is after/follows the question mark. If yes, then it matches the characters mentioned above. The question mark quantifier can be useful when you are expecting two different but acceptable inputs from a user. But the Regex. In order to make it meaningless to preg_replace, you have to escape it using \. The pattern starts with a (?x) which is an unfamiliar regex to me. OR statement and REGEX in Python. But the catch is that you have to precede typing a question mark with Ctrl-Shift-v in order for it to be interpreted as a question mark and not a help command Link to Cisco regex guidelines. Why would you need to escape the apostrophe? Firstly note that In Emacs regexp syntax, \` matches the start of the string, and \' matches the end of the string. Thus, you may fix the code with In the text are nine sentences by question mark, but it's working only for one: He himself was a very old man with shaggy white hair which grew over most of his face as well as on his head, and they liked him almost at once; but on the first evening when he came out to meet them at the front door he was so odd-looking that Lucy (who was the youngest) was a little afraid of him, and As you say, ? sometimes means "zero or one", but in your regex +? is a single unit meaning "one or more — and preferably as few as possible". POSIX (BRE/ERE) doesn't have an escape character inside character classes. It then goes home satisfied. ). When is the next time it Try this: Regex. (9-! wouldn't be a valid range anyway because ! is before 9 in ASCII order. *(def) against abc defg:. The second match in the remaining string is the character 'c'. )Likewise a -at the start or end of a character class is literal, for example in /[-a]/, /[a-]/ or even the negative character class /[^-a]/. * as far as possible, then checks if the regex can match the input. Java RegEx implementation deems following characters as word characters: \w:= [a-zA-Z_0-9] Any non-word characters are simply ones outside the above group [^\w]:= [^a-zA-Z_0-9] Word boundary is a transition from [a-zA-Z_0-9] to [^a-zA-Z_0-9] and vice-versa. I need to pass on any parameters that appear after /user/friends as is. See What special characters must be escaped in regular expressions? . Provide details and share your research! But avoid . In your case, it does, since the trailing slash is optional. Question marks followed by non-digits are left unchanged. Asking for help, clarification, or responding to other answers. [?\s] Match a question mark, or whitespace. The difference between firefox and IE is trivial. 1. I looked it up in an online regex tester, which seems to say that it's invalid. How to exclude question mark from a string? Hot Network Questions Does riding a single-speed provide a superior workout? UK Company liquidation implication on ex employee dependents How common is it for customers with connecting flights to be routed through immigration check? Assume we have the string acac123. What am I doing wrong? c#; regex; escaping; Share. But when I try to set up rules for URLs with qu The [a-zA-Z0-9\?]+ matches one-or-more occurrences of the characters given in the character class i. So can i replace the (?) sign in my text with (\\?) to fix the pattern problem ? You are matching using word boundaries: \b. It is incorrect to use a regular expression for such a task in PHP. Follow edited Oct 28, 2011 at 22:06. Hot Network Questions If you want to match all quotation marks and question marks as your question states, then your pattern is okay. Hot Network Questions There are many errors in your answer, including but not limited to: None of your "modern" flavors require -or ] to be escaped outside character classes. If I make my regex be "\. MySQL would see a single \ character and attempt to use it as an escaping character within the SQL statement itself rather than treating it as a literal. ? is a quantifier meaning zero or one instances of the preceding atom, or (in regex variants that support it) a A single backslash is the correct way to escape a question mark \?. In this lesson, we'll shed light on this intriguing aspect of regex. Well, groups serve many purposes. This article will explore how to effectively use question marks in regular expressions, providing examples Learn how to use the question mark (?) quantifier to make a character or group optional in regex. javascript regular expression question mark after parentheses. The safest way to store a list of options and arguments in variables is to use an array:. Match Question Mark in mod_rewrite rule regex. Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. In regex, the question mark is a special character that indicates that the preceding character or group is optional. When I see {0,1}, {0,} or {1,} being used in a question, it's virtually always being done out of ignorance. Mod Rewrite with question mark in result. Yes it is I want to find a question mark that is followed by a space and an upper case letter. Add a comment | 1 Python regex. I have a Go program that logs into a set of devices and runs a set of commands on each device If I change the question mark to any other character it works great. JPG$", the result became "acceptable". And in the process of answering such a question, we should also suggest that they use the ?, * or + instead. You have a question mark followed by a space, so there is no word boundary there and the regex will not find one. It seems like the problem is that the '?' character is being interpreted incorrectly as the start of a new query string. To see How to properly escape question mark in regex? Hot Network Questions Did Lebesgue consider the axiom of choice false? How could an Alcubierre/Warp Drive work in my science-fantasy story? Problems with relaxed PES scan Combining Question Marks with Other Regex Features. However that is not relevant within a character I have this regex : new RegExp("^[A-Za-z\\u00C0-\\u017F][\\- ]?+$"); It validates a first name. Java pattern to match new RegExp('http:\/\/(?!' + location. I thought question mark (?) in regex means 0 or 1 times regex rule. 76. ; Since this causes the rest of the match to fail, the regex engine backtracks until it finds a way to match Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company Visit the blog As far as I know, most regex engine is greedy by default. I can't match the question mark character although I escaped it. The thing is the use of question mark and equal to symbol in regex. ) any number of times (*), as few times as possible to make the regex match (?). Here’s how to implement this: By default, sed uses the " POSIX basic regular expressions syntax", so the question mark must be escaped as \? to apply its special meaning, otherwise it matches a literal question mark. URL Rewriting with a ? symbol . The question mark makes the previous statement optional and in your case only makes the 's' and the 'i' optional xmln s ?xs i ?[a-zA-Z\d-=":/. It can be used to check if a string contains the specified pattern, to check if a string matches the pattern, or to replace parts of a string with That is almost the same but has only the question mark "chk-error/? I would like to make it optional. First, the engine starts trying to match the regex at the beginning of the string. The dot: . For more information, go, read each function's description on PHP manual: preg_replace; str_replace Here's what happens when the regex engine tries to match . So in the example in your question, [ -]\? matches either a A literal question mark. htaccess url rewrite with question mark. markb A regular expression (regex or regexp) is a sequence of characters that forms a search pattern. Consider the regex pattern (abc)?def, which will match “def” or “abcdef”. Also, the fact that the special chars can appear at the leading/trailing positions means you cannot expect \b to always work the same (since its meaning is context dependent). Replace(str, @"\?(\d)", @"Rs$1") It will match a literal question mark followed by a digit and replace it with Rs followed by that digit. This exception can be overridden in <oXygen/> by checking Dot matches all in the Find-and-replace dialog, in which case the dot will match absolutely all characters, including newlines. Javascript Regexp Question Mark Cross-Browser Behavior. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their I'm trying to learn Atom's syntax highlighting/grammar rules, which heavily use JS regular expressions, and came across an unfamiliar pattern in the python grammar file. Exercise 1: Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company I expected my program to return "acceptable" but it returned "unacceptable" instead. – EDIT: As requested, let me try to explain groups too. Java regex matching either a word or a punctuation sign . How to properly Consider though that it may be faster not to use regex and just do a simple "string contains" check for the presence of a question mark if that's literally all you're doing, and don't require complex pattern matching and value capture The regex engine consumes the matched substring, so the string 'c dd ee' remains. String constants (such as "A\?B") are scanned twice:. Regex using the ? Operator in java. Question mark with equal to sign in regex. Javascript regex doesn't match. I need to exclude a question mark from a string using the exclusion of that character, but I still get some undesired results. Please help! I need a regex for setting access level of certain URLs in Apache httpd. Regex for extracting string with interrogation (?) mark in Python. Viewed 6k times 1 . So far I've figured out how to match the question mark using. Unlike some other quantifiers which focus on repetition, the question mark quantifier is all about optionality. e. Removing Characters before exclamatory mark in a String. Regex (short for regular expression) is a powerful tool used for searching and manipulating text. Javascript in regexp not matching something . "foo?") where \? escapes the question mark in the regular expression so that it is treated literally, rather than as a regular expression operator. I have to get any link (as text) that doesn't have a question mark, for example, I have to exclude an URL like: Escape the question mark and dots so that they are treated as literals. In this example, the author wants to ensure the character after MyClass is not a whitespace character ( \S ). The answer to how you should check the match results is I need to replace a black diamond with a question mark in a windows service. But in a few dialects, it's the other way around. See the regular expression, test string examples, and detailed explanation of the regex syntax One of the most versatile characters in regex is the question mark (?). Johan. As @Andre S mentioned in comment. Improve this question. 2k 27 27 gold badges 199 199 silver badges 332 332 bronze badges. Can't figure out what's going on with RegExp question mark. Hot Network Questions Projective automorphisms of a plane cubic curves Are there different versions of Mozart's Ave Verum Corpus? Regexp question mark (in emacs) 31. represents any single character (usually excluding the newline character), while * is a quantifier meaning zero or more of the preceding regex atom (character or group). a-z, A-Z and digits from 0-9, and the question mark ?. From MSDN:. My initial thought was it represents an optional left Hey Experts i am new to regex. 9-! doesn't act as a range in the second regex because the 9 is already part of the 0-9 range. The name have to begin with a letter (the range is in unicode and works fine) and then continue with letters or - or space. Guoxing Li Guoxing Li. Follow edited Jul 23, 2015 at 11:07. Python regular expression match in html file. Searches the input string for the first occurrence of the specified regular expression. So in this case it has four elements, the total matched string, "aaa", the first sub result, "aaa" again, and both (\s*(\w+)) and (\w+) have empty matches. ; No need for option g, since you're only replacing 1 occurrence per line. The reason your regex is not working is the \b at the end. See examples, usage scenarios, pitfalls and exercises on RegexRoo. RegEx - Not parsing dot(. The difference between str_replace and preg_replace is, preg_replace do replacement using regex. Python regular expression in html . $ Match the end of the string. 0. In this chapter, we will slightly move away from regular expressions and focus on string manipulation by creating strings from other data structures like vectors or lists. For instance, you can use it with groups to make entire sections of a pattern optional. See examples of how to reduce greediness and handle different inputs with the zero or one quantifier. g. Lovecraft to R. How to properly escape question mark in regex? Hot Network Questions Getting a peculiar limit of sequence Where in the world does GPS time proceed at one second per second? Is there a map? What would the exhaust of a decelerating antimatter rocket look like to an observer on Earth? Would it be considered inappropriate or impermissible ex parte communication if no legal When you use a backslash to escape a regexp character in MySQL, you must also escape the backslash itself as \\. Defining the Question Mark I get /api/things/index, but nothing after the question mark. Would you like us to guess about the rest of your code to figure out why it's not working for you? Would you like us to guess about the rest of your code to figure out why it's not working for you? But I can't recall ever seeing such a case in real life. – Learn how to use the question mark (?) to make the preceding token optional in regular expressions. The regex Great\? matches the literal string Great followed by a literal question mark. I have a hive query to filter out '/s?' from the data but it doesn't seem to work and I am getting very broad matches Yes, that pattern will match a period, exclamation mark, or question mark. Regex to ignore trailing dot if there is one. Python parsing HTML Using Regular Expressions. In most regex implementations, a question mark means that the previous item is optional, while an escaped question mark (\?) is a literal question mark. regular expression by question mark (Java) 0. * initially tries to match as many times as it can, matching the entire string. I tried the very same regex here and it worked. The problem is that Regex. In regex, the dot corresponds to any character except a newline character. If the question mark is not properly escaped, it may be interpreted as a literal question mark by the regex engine, leading to incorrect matches or ? is not a metacharacter in basic grep, so if you're grepping for a?, you are in fact grepping for a followed by a question mark. As an alternative, you can use the -r or --regexp-extended option to use the "extended regular expression syntax", which reverses the meaning of escaped and non-escaped special Allowing Asterisks And Question Marks In A C# RegEx pattern. Question Mark vs Plus. Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company how do I find all sentences with a question mark at the end? Specifically the character immediately after . Exercise 11: You can now read this! Chapter 2: Creating Strings with Data. What other modern or near future weapon could damage them? Identifying data frame rows in R with Not escaping question marks in regex expressions can lead to unexpected and incorrect results. Stack Overflow. – Wiktor Stribiżew Regex can't escape question mark? [duplicate] Ask Question Asked 10 years, 2 months ago. matching html tag using regex in python. Modified 10 years, 2 months ago. I tried escaping with multiple backslashes But it does not match the empty string because the asterisk quantifier * does not apply to the whole regex ‘yes’ but only to the preceding regex ‘s’. Some special cases of this in questions that are old and well written enough for it to be cheeky to close as duplicates of this: Escaped Periods In R Regular Expressions How to escape a question mark in R? escaping pipe ("|") in a regex Wait a minute ! Sabuj, and Jerry too, you have both out thought me. Viewed 5k times 2 This question already has an answer here: match trailing slash with Python regex (1 answer) Closed 10 years ago. + One or more times. You can read the Python Re A? quantifier as zero-or-one regex: the preceding regex A is matched either zero times or exactly once. 189 1 1 gold badge 3 3 silver badges 8 8 bronze badges. mjj lqms pleym uryk hluxt kchgv tcu bbpf kaeg eylril