Regex question mark in brackets. regular expression by question mark (Java) 2.
Regex question mark in brackets Provide details and share your research! C# regular expression to match May 18, 2017 · I am trying to mark word or sentence with single bracket, this bracket may be place in left or right and middle of word or sentence. Thank to everybody who answered. Aug 27, 2021 · matches anything in brackets unless there is a question mark right after the last bracket. Again, please reference the example test strings at Rubular. *?)]" is interpreted as a character class. @Matt Clarkson what I am trying to match is a judicial decision 'handle' in a much larger text. Why is this? Feb 20, 2010 · To make a regex non greedy (lazy) put a question mark after your greedy search e. The thing is the use of question mark and equal to symbol in regex. Inside the regular expression, a dot operators represents any character except the newline character, which is \n. Matches any single character within the brackets. PowerShell is a cross-platform (Windows, Linux, and macOS) automation tool and configuration framework optimized for dealing with structured data (e. * means "zero or more of the preceding item". Feb 3, 2017 · See this Stack Overflow question for more details. Then it matches zero or more characters that are either a line break or white space. 'elephant'. 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. I have found something which is very difficult to understand for me. 1. * will again consume the entire string. In the meantime, guess we'll have to refer to this old StackOverflow question: Matches the preceding character or character group in the regular expression one or more times. The period . (or dot) character in regex is called a wildcard because it matches any character except for a newline. in a regular expression matches any single character. pipe (|) Matches the preceding character (or character group) or the following character (or character group). Oct 18, 2012 · Opening square bracket [Backslash \ Caret ^ Dollar sign $ Period or dot . 0. These lines would have square brackets changed into apostrophes: [que] vão levar [vocês] ao [limite]. below is an example of a string I'm using: [REGEX:^([0-9])*$][ Dec 31, 2014 · Note that in cases the regex you build has nothing on its sides, you will most probably also want to sort the values by length in descending order first, because regular expression engines search for matches from left to right, and user-defined lists tend to contain items that may match at the same location inside the string (=values inside Dec 1, 2012 · In this part we will just look at one group of symbols in depth, the brackets. To create a regex that matches cat food or dog food, you need to group the alternatives: (cat | dog) food. Match(str, pattern, RegexOptions. Let’s see an example for the same. Let’s have another look inside the regex engine. *?) matches any character (. +?\]\((. Dec 8, 2008 · You problem may come from the fact you are using eregi_replace with the first parameter enclosed in simple quotes: '\[' In double quotes, though, it could works well depending on the context, since it changes the way the parameter is passed to the function (simple quotes just pass the string without any interpretation, hence the need to double to "" character). Optional means it exists once or it doesn't exist. You can make several tokens optional by grouping them together using parentheses, and placing the question mark after the closing parenthesis. The dot: . the sequence \w means "any alphanumeric character or underscore". Well, groups serve many purposes. (\w+) # Capture a word. When I move the question mark to after the square bracket (\d[^\w]?\d), the matches are now 30, 01, 20, 03, 15, and 20. Repetition. The question mark makes the preceding token in the regular expression optional. Viewed 3k times Sep 13, 2016 · Here, the parser doesn't have to capture anything at all to get a match: the asterisk allows any number of characters in the capturing group, while the question mark makes the parser save as many as possible from the input text for later, resulting in nothing being captured. That's why it's called optional. M (multi-line), re. Nov 5, 2011 · In most regex implementations, a question mark means that the previous item is optional, while an escaped question mark (\?) is a literal question mark. [] square brackets. (?![^\s])-> Negative lookahead to ensure there should not any non space character after the previous match In the following example, the regular expression "[(. The reason for this is that brackets are special regex metacharacters, or characters which have a special meaning. An eg : Dec 28, 2020 · Colon : is simply colon. Needless to say the regex bit isn't working. You'll get a match on any string, but you'll only capture a blank string because of the question mark. Oct 19, 2010 · Use Regex Subtraction [\p{P}-[. Though the syntax for the named backreference uses parentheses, it’s just a backreference that doesn’t do any capturing or grouping. You can do that by putting a question mark after the plus in the regex. , the pipe symbol |, the dollar sign $, the question mark ?, the asterisk *, the plus sign +, the opening and closing parenthesis ( ), the opening square brackets [ and the opening curly bracket {. Oct 5, 2008 · After encountering such state, regex engine backtrack to previous matching character and here regex is over and will move to next regex. Mar 21, 2012 · The optimal regex is /^[789]\d{9}$/, because /^(7|8|9)\d{9}$/ captures unnecessarily which imposes a performance decrease on most regex implementations (javascript happens to be one, considering the question uses keyword var in code, this probably is JavaScript). That is why given regex. Oct 29, 2015 · Try using this regex instead: \[. For example, the plus sign (+) is a quantifier in REGEX, meaning one or more of the preceding element. For example, [a-z] matches one lowercase letter from a to z, or T[ao]p would match either Tap or Top. I'm don't have to make sure if the mentioned airport code is correct. \1-> Matches to the character or string that have been matched earlier with the first capture group. The question mark in . Regular expressions with question mark. Mar 30, 2017 · I like to use raw strings for my regex patterns, even though it's not always necessary. | (pipe): Acts as an OR operator, matching either the expression before or after it. [ ] (square brackets): Defines a character set. g. So that's why it started at the first bracket in your first attempt, instead of the first one before your word as you intended. Please be sure to answer the question. – Aug 30, 2011 · It's easy when you understandunfortunately, I don't! I will deeply appreciate you if you can guide me to the answer, thanks. match(/[abcd]/) // -> matches 'a' You can use the ^ metacharacter to negate what is between the Aug 18, 2010 · EDIT: As requested, let me try to explain groups too. As you can see from the output that after adding a question mark operator after the curly brace operator, it tries to match the minimum number of characters as possible i. [another one] What is the regular expression to extract the words within the square brackets, ie. Had no idea the regex code in g++ was incomplete. split("(\\r?\\n|\\r)+"); Lines will be split at "\r\n", "\n" and "\r", but that's effectively the same as: String lines[] = inputText. [^] carat enclosed in square brackets Mar 8, 2012 · However, if a quantifier is followed by a question mark, then it becomes lazy, and instead matches the minimum number of times possible, so the pattern /\*. The other, as I used in my answer, is to specify that the match is not greedy by affixing a question mark after it. ) any number of times (*), as few times as possible to make the regex match (?). *?\*/ does the right thing with the C comments. I (ignore case), re. C# example string pattern = @"[\p{P}\p{S I stumbled on this question while dealing with square bracket escaping within a character class that was designed for use with password validation requiring the presence of special characters. ), then it tries to look ahead for characters that are not c, e, k, / or between n and z. Although not working for your application, my answer's regex provides three match groups: 1) any char until second match group—group is returned; 2) brackets and chars within–NON-capturing-group, thus group not returned; and 3) any char after second match group Feb 2, 2018 · Square brackets ( “[ ]” ): Any expression within square brackets [ ] is a character set; if any one of the characters matches the search string, the regex will pass the test return true. JSON, CSV, XML, etc. We know the area code will always be the first three digits we see, so there is no need to complete the regular expression so that it matches the entire line. * consumed everything but the pattern still has to match b afterwards), it will backtrack , one character at a time, and try to Match either the regular expression preceding it or the regular expression following it. (The flags are described in Module Contents. Here is an (incomplete) list of open delimited grouping constructs. ) Feb 4, 2022 · The regex Great\? matches the literal string Great followed by a literal question mark. ab{2,4} Dec 11, 2010 · Try this: \?(. Sep 18, 2012 · Your second regular expression ought to work. Regular Expression: brackets inside Square brackets. sample some another one Note: In my use case, brackets cannot be nested. The braces can pretty much contain any three capital letters. Sep 9, 2016 · In regular expression syntax . Match any single character from within the bracketed list, as in [abcde]. The backslash before the question mark makes it a literal match on the question mark character. If you need to get the value inside square brackets excluding the square brackets, you can use a PCRE regex based grep In the following example, the regular expression "[(. Jan 30, 2003 · When I try adding a question mark at the end of the regex (\d[^\w]\d?), my matches don't change. \)\(-]+ but, since you're complicating the expression, you'll probably need to check for balance as well. Question Mark. This feature is much more useful when you have a more complicated regex. Multiline) Mar 28, 2013 · Thanks for the hint. regextester. So, it would match ‘ab’, ‘aab’, ‘aaab’, etc. * will simply match until the end of the line if that's a valid match. To use a literal plus sign in a REGEX pattern, you would use the escaped character \+. Something like "How can I fix this?" to the end would be sufficient. In Perl extended notation: s/ ^ # Beginning of string. compile Simple regex question. In order for regex to match a dot, the dot has to be escaped: \. In other words, that regex is quite happy to accept 74. Rather than matching comments embedded in the input text, the regular expression matches each opening or closing parenthesis, period, asterisk, or question mark. L (locale dependent), re. Jun 12, 2012 · Inside the square brackets, you want any sequence of characters EXCEPT a close square bracket. ( ) (parentheses): Groups characters together and creates a capturing group. Modified 8 years, 7 months ago. Test your skills and track progress; Engage in comprehensive interactive courses; Commit to daily skill-enhancing challenges; Solve practical, real-world issues Dec 7, 2012 · @Jdoe - Your question was very close to good. Oct 28, 2024 · Character class: Matches any one of the enclosed characters. As a special character, which is also a quantifier in this case, it matches 0 OR 1 of the preceding character. 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. This operator cannot appear after an opening round bracket, because an opening bracket by itself is not a valid regex token. Jul 3, 2012 · I'm trying to find aiport codes given a string like (JFK) or [FRA] using a regular expression. Vertical bar or pipe symbol | Question mark ? Asterisk or star * Plus sign + Opening round bracket (and the closing round bracket ) Opening curly bracket {Pound/Hash sign # These special characters are often called "metacharacters". If you don't set a flag or add a question mark then quantifiers are usually greedy, so . However, since the engine will have reached the end of the string and the pattern is not yet satisfied (the . split("(\\n Aug 24, 2012 · Looking for a pattern for matching text between brackets. g *? ?? +? What happens now is token 2 (+?) finds a match, regex moves along a character and then tries the next token (\b) rather than token 2 (+?). Use a hyphen (-) for a range, as in [0-9]. The question mark is called a quantifier. 1 day ago · Regular Expression HOWTO If the first character after the question mark is a P, such as the angle brackets surrounding an HTML tag. By contrast, . S (dot matches all), and re. For example: "(this is) a (test)" should output "this is" "test" Using Dim m As Match = Regex. Reply afro_coder • Jun 16, 2011 · Well, you can just add them to the regex with something like [0-9. regular expression by question mark (Java) 2. *?)\] and replace the match with '\1' Demo. Dec 8, 2024 · A Regular Expression or RegEx is a special sequence of characters that uses a search pattern to find a string or set of strings. There are a couple of ways to handle that. *? / +? A question mark Aug 3, 2015 · @desioner Glad you found a working answer. May 2, 2023 · Regular expression to extract text between square brackets 923 Regex for password must contain at least eight characters, at least one number and both lower and uppercase letters and special characters Apr 5, 2018 · Usage of question mark in regular expression. it replaces the entire string with "d" in this case. Long story short, with REG_EXTENDED, you get the grep -E (aka egrep) meaning of some regex constructs. Share. It means nothing, except special cases like, for example, clustering without capturing (also known as a non-capturing group): (?:pattern) Jun 15, 2021 · Python regex metacharacters Regex . Note the question mark after the opening bracket is unrelated to the question mark at the end of the regex. cat | dog food matches cat or dog food. Unless modified by other regex operators, it will stop after finding one: Oct 3, 2010 · Now, when the regex engine tries to match against aaaaaaaab, the . * matches as many characters as possible. I am really confused by studying this regex. * is ''greedy'', meaning it will take as many characters as it can, including any brackets. info Nov 6, 2024 · The question mark makes the preceding token in the regular expression optional. It has been pointed out to me that inside square brackets [] a dot does not have to be escaped. I'm not sure if other flavors support it. So, your regular expression is looking for any string that begins with either a backslash or a question-mark. (question mark): Matches zero or one occurrence of the previous character or group. , the vertical bar or pipe symbol |, the question mark ?, the asterisk or star *, the plus sign +, the opening parenthesis (, the closing parenthesis ), the opening square bracket Sep 13, 2016 · (. " The engine realizes that the s could work as part of [a-z]+|\d+, so it prefers to put it into Group 2. , but it would not match ‘b’, as this does not have an ‘a’ character before the ‘b’ character. Doesn't it, really? And if so, is it true for all regex standards? Nov 16, 2022 · The question mark operator denotes that we are looking for either a left or right parenthesis or none at all. The {3} part is not relevant to the question, I used it to find 3 consecutive question marks. But it doesn't work for the described case. [ ] Brackets indicate a set of characters to match. It indicates to the regex engine that the contents of the group should be saved for later use. Similarly, to use a literal question mark (?), which is another quantifier meaning zero or one of the preceding element, you would use the escaped character \?. Apr 15, 2019 · I'm trying to do the following to have the second group repeated, however regex seems to think I'm closing brackets earlier/later than I want, causing errors: ERROR: Unmatched closing parenthesis I'm using https://www. I have a string on the following format: this is a [sample] string with [some] special words. You can specify a range of characters by using a hyphen, but if the hyphen appears as the first or last character enclosed in the square brackets, it is taken as a literal hyphen to be included in the character class as a normal character. Your original regular expression only matches a single character (the . We do not match until the end of the string. , the vertical bar or pipe symbol |, the question mark ?, the asterisk or star *, the plus sign +, the opening parenthesis (, the closing parenthesis ), the opening square bracket Aug 12, 2021 · This can be done by adding a question mark after the curly braces operator. *? causes . Note the double escaping: The question mark, represents the optional character based on how you use it (it can do other things). Oct 27, 2020 · Regular Expression to match parentheses and brackets for JavaScript Hot Network Questions Why does one have to avoid hard braking, full-throttle starts and rapid acceleration with a new scooter? I have a string that contains a regular expression within square brackets, and can contain more than 1 item inside square brackets. javascript regular expression question mark after parentheses. The meaning of the various quantifiers is not otherwise changed, just the preferred number of matches. colo u? r Feb 27, 2012 · That question mark is the regex operator that makes the previous token optional. the parentheses surrounding \w*-d is a capturing group. One is to specify [^\]]* (explicitly specifying "not a close square bracket"). If you want to support cases where there is no question mark, then just remove the final \?. ]{3} would match string. Jan 3, 2019 · 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 Dec 27, 2016 · A dot . You can do the same with the star, the curly braces and the question mark itself. colo u? r matches both colour and color. *) The parentheses are a capturing group that you can use to extract the part of the string you are interested in. What follows is a character or characters that uniquely identifies what the group does. Sep 5, 2016 · Part of the problem here stems from an unfortunate confusion between the feature sets of different regular expression dialects. Other words or sentence in regex101 tool should not be disturb Jun 12, 2013 · abc, d are unrelated. If the string can contain new lines you may have to use the "dot all" modifier to allow the dot to match the new line character. When a regular expression is quoted as a literal in a programming language, then the string or regex formatting rules of that language may require / or " or ' to be escaped, and may even require `\` to be Nov 3, 2022 · Certain characters have special meaning in regex and if you wish to use them literally then you must escape them, a quantifier bracket is something like {3} The end of your regex has a lone quantifier bracket; it should be escaped: Aug 13, 2012 · First, the question mark which supposedly should either make the preceding item optional or specify that the preceding quantifier make lazy, but there is no item or quantifier here, only the start of a new group so what effect does it have here? May 29, 2009 · In the general case, the two backslashes are wrong here. For example, the expression: [. Therefore, there is no confusion between the question mark as an operator to make a token optional, and the question mark as a character to Apr 28, 2014 · It should be stated that . Any individual character between the brackets will match, and you can also use a hyphen to define a set. Learn more about alternation. Aug 26, 2014 · The date regex at the end only matches cases with dates in square bracket but not the ones without. E. When I move the question mark to before the square bracket (\d?[^\w]\d), my matches are the same as in the first case. In regex, the dot corresponds to any character except a newline For instance, the regular expression ‘a+b’ would match any string that has one or more ‘a’ characters, followed by a ‘b’ character. These characters are the backslash \, the caret ^ sign, the dot or period . Mar 21, 2023 · To only make replacements when both left and right brackets are present use the regular expression \[(. Within square brackets, most characters are interpreted literally. The question mark makes it instead match as few characters as possible. Nov 6, 2024 · Alternation has the lowest precedence of all regex operators. Again, < matches the first < in Apr 17, 2018 · Note that it will also ensure that there is a question mark. I want to capture a string, using just regex, but remove any text th Feb 17, 2013 · The question mark inside square brackets is literally a question mark. In some languages (like Java, Python if not in a literal r"" string, etc) you need to backslash the backslash to pass it through to the regex engine as a single backslash, but that's a (mis)feature of the host language, and not a correct answer for a question asking simply about regular expressions without a specific host language. Jul 2, 2020 · The Wildcard Character. This version of a Backreference only works in AutoMod if the regex syntax is the only/first one in the rule (in that specific check), because behind the scenes the whole list of syntaxes/keywords is converted into one big regex and so the number of the parenthesis doesn't stay confined to the specific regex it's from. Regex to extract word inside round brackets. Sep 9, 2016 · The -o option makes grep output matched substrings only, not whole lines, and the \[[^][]*] pattern matches a [, then 0 or more occurrences of any chars but [and ] (see the negated [^][]* bracket expression), and then a ]. _]] See the . to split your strings by line without extra spaces at the start of the next line and exact contains the string with the sign delimiter - you should use String regex = "(?<=[. Sep 2, 2016 · I'm trying to find a way to replace square brackets into apostrophes for some subtitle files, but only for cases when these square brackets do not contain a whole sentence having the square brackets at the beginning & end of the line. Oct 24, 2011 · To fix this, you make one tiny change: Pass/Fail Group 1 Group 2 Grouped correctly? Essentially, this means: "Match https if you have to, but see if this still passes when Group 1 is just http. So it creeps along gingerly. (capture group (? modifier group (?: cluster group (?# comment group Mar 6, 2012 · The Input Line goes like this (just a part of it): [[Text Text Text]][[text text text]]asdasdasdasda[[asdasdasdasd]] What I want is to list all matches wherein text enclosed in a pair of [[ and ] / is not a metacharacter in any of the regular expression flavors I mentioned, so the regular expression syntax does not require escaping it. From the Wikipedia article and other references, I've concluded it means the former at the start and the latter when used with brackets, but how does the program handle the case where the caret is at the start and at a bracket? The question mark and the colon after the opening round bracket are the special syntax that you can use to tell the regex engine that this pair of brackets should not create a backreference. * to match as few characters as possible, so it will not match ']'. So our example becomes <. 7(((((2) which is not really well-formed. The Question Mark Metacharacter Dec 4, 2015 · That is, I enclosed the question mark in character class brackets ( [and ]), which made the special meaning inactive. !?])\\s*" Nov 5, 2021 · Test your skills and track progress; Engage in comprehensive interactive courses; Commit to daily skill-enhancing challenges; Solve practical, real-world issues Feb 19, 2014 · Following that is a question-mark ? - which, when placed inside brackets, literally means you want to match for the question-mark symbol. *)\) As @PM 77-1 pointed out, you need to escape the brackets by placing a backslash in front of them. Jan 8, 2014 · Hey Experts i am new to regex. Any character means letters uppercase or lowercase, digits 0 through 9, and symbols such as the dollar ($) sign or the pound (#) symbol, punctuation mark (!) such as the question mark (?) commas (,) or colons (:) as well as Jul 2, 2013 · When a string is interpolated as a regex, it isn't matched literally, but interpreted as a regex. Square Brackets. Next time make sure your title attempts to describe your problem, "I need a regular expression" is too vague (I edited your question to fix this). while question mark Nov 12, 2013 · That Regex would only work for up to 3 occurrences of "quoted strings" inside a set of brackets. You might not need this. Brackets tell the regex engine to look for classes of characters contained inside of it. Reply reply Oct 1, 2013 · 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 Nov 6, 2024 · Lazy quantifiers are sometimes also called “ungreedy” or “reluctant”. Example 4: Implementing Wildcard atRegex = re. Nov 6, 2024 · In the regex flavors discussed in this tutorial, there are 12 characters with special meanings: the backslash \, the caret ^, the dollar sign $, the period or dot . See full list on regular-expressions. Ask Question Asked 8 years, 7 months ago. the simplest way to put the sign in square brackets String regex = "[?]" but if you need e. But in a few dialects, it's the other way around. The question mark (?) in a regular expression has several meanings and may define: a quantifier a lazy match a group name property a look-around (assertion) And to determine what is its meaning, it just depends on the context where it's used. Also, even though it was clear what you wanted, include a question. The brackets can be used in compound structures, such as [A-C][0-3][g-i], so that you would match strings of A0g, A0h, B1i, and C3g For ease of use, to denote the start of a complex construct, the question mark ? follows the open paren, like so (?. Any explanation or aid would be great! EDIT: I tried another regex, \[([^\]]{0})\] This one worked for the case where brackets contain no inner brackets and nothing else inside. I added tags and a link to the question to clarify it uses regex with find-and-replace. For example, [abcd] is the same as [a-d]. NET Regex documentation. opening bracket ([) and closing bracket (]) The opening and closing brackets and the enclosed character group define a character class. This is useful to build complex regexes, e. (need to capture including brackets) ignore this (ignore this completely)? This pattern captures the top line in brackets correctly without including the space, but also captures the line below which I want to ignore: The question mark, P, angle brackets, and equals signs are all part of the syntax. Here's my current solution which does work for round brackets but not for square brackets: [((\[]([A-Z]{{3}})[))\]] Thanks! Jun 1, 2017 · Specifically when does ^ mean "match start" and when does it mean "not the following" in regular expressions?. You could however extend the regex string to grab up to N occurrences as follows: The regex to find 1 to N quoted strings within each set of parenthesis is: Feb 28, 2007 · Notation Characters Matched Example \d: Any digit from 0 to 9 \d\d\d matches 101 but not 10a \D: Any character that is not a numeric digit (0 to 9) \D\D\D matches abc but not 101 \w: Any word character, for example, a-z, A-z, 0-9, and the underscore character _ (also matches Unicode-based word characters from non-latin alphabets and scripts). Replace square brackets with round ones(the former is limited to ONE character for each alternation): String lines[] = inputText. com for this. . ), REST APIs, and object models. +? >. represents any single character Within POSIX bracket expressions, the dot character matches a literal dot. Sep 25, 2015 · The group matches the empty string; the letters set the corresponding flags: re. : Nov (ember)? matches Nov and November. e it becomes nongreedy. A (ASCII-only matching), re. The square brackets [ ] are used to match specific characters, which are defined within the square brackets. X (verbose), for the entire regular expression. dot metacharacter. Jun 13, 2013 · You can use non-qreedy quantifiers. kvyszvt imwovj yudsyb aktqac rmvqare cxgjue vdhi nvwahp grq zwlswz