i need a regexp which returns all parts of a string which has parenthesis.  An example would be:  if ((a and b) or (a and)) or (c and d) or (e and f)   would return  ['if', '((a and b) or (a and))', 'or', '(c and d)', 'or', '(e and f)']   .  Can anybody direct me how could i achieve it? Unfortunately i don' t have a very deep friendship with re .  The biggest problem is the "parenthesis inside a parenthesis" .  Many thanks.
5414
I need a regular expression to select all the text between two outer brackets.  Example: some text(text here(possible text)text(possible text(more text)))end text  Result: (text here(possible text)text(possible text(more text)))
23363
Given the URL (single line):   How can I extract the following parts using regular expressions:   The Subdomain (test) The Domain (example.com) The path without the file (/dir/subdir/) The file (file.html) The path with the file (/dir/subdir/file.html) The URL without the path () (add any other that you think would be useful)   The regex should work correctly even if I enter the following URL:    http://example.example.com/example/example/example.html
62549
I'm having a bit of trouble getting a Python regex to work when matching against text that spans multiple lines. The example text is ('\n' is a newline)  some Varying TEXT\n \n DSJFKDAFJKDAFJDSAKFJADSFLKDLAFKDSAF\n [more of the above, ending with a newline]\n [yep, there is a variable number of lines here]\n \n (repeat the above a few hundred times).   I'd like to capture two things: the 'some_Varying_TEXT' part, and all of the lines of uppercase text that comes two lines below it in one capture (i can strip out the newline characters later).  I've tried with a few approaches:  re.compile(r"^&gt;(\w+)$$([.$]+)^$", re.MULTILINE) # try to capture both parts re.compile(r"(^[^&gt;][\w\s]+)$", re.MULTILINE|re.DOTALL) # just textlines   and a lot of variations hereof with no luck. The last one seems to match the lines of text one by one, which is not what I really want. I can catch the first part, no problem, but I can't seem to catch the 4-5 lines of uppercase text. I'd like match.group(1) to be some&#95;Varying&#95;Text and group(2) to be line1+line2+line3+etc until the empty line is encountered.  If anyone's curious, its supposed to be a sequence of aminoacids that make up a protein.
262
I don't really understand regular expressions.  Can you explain them to me in an easy-to-follow manner?  If there are any online tools or books, could you also link to them?
4492
That was an interview question that I was unable to answer:  How to check that a string is a palindrome using regular expressions?  p.s. There is already a question "" and it gives a lot of answers in different languages, but no answer that uses regular expressions.
10097
Does Java have a built-in way to escape arbitrary text so that it can be included in a regular expression? For example, if my users enter "$5", I'd like to match that exactly rather than a "5" after the end of input.
33382
Can a regular expression match whitespace or the start of a string?  I'm trying to replace currency the abbreviation GBP with a £ symbol. I could just match anything starting GBP, but I'd like to be a bit more conservative, and look for certain delimiters around it.  &gt;&gt;&gt; import re &gt;&gt;&gt; text = u'GBP 5 Off when you spend GBP75.00'  &gt;&gt;&gt; re.sub(ur'GBP([\W\d])', ur'£\g&lt;1&gt;', text) # matches GBP with any prefix u'\xa3 5 Off when you spend \xa375.00'  &gt;&gt;&gt; re.sub(ur'^GBP([\W\d])', ur'£\g&lt;1&gt;', text) # matches at start only u'\xa3 5 Off when you spend GBP75.00'  &gt;&gt;&gt; re.sub(ur'(\W)GBP([\W\d])', ur'\g&lt;1&gt;£\g&lt;2&gt;', text) # matches whitespace prefix only u'GBP 5 Off when you spend \xa375.00'   Can I do both of the latter examples at the same time?
111512
I am using this method to try find a match, in an example:  Regex.Match("A2-TS-OIL", "TS-OIL", RegexOptions.IgnoreCase).Success;   I got a true result. I am confused. I think this should return false since there is no special characters in the pattern. If I use ".+TS-OIL", true should be returned (. for any and + for more than 1). How should I do to get what I need?
71596
expr does not seem to like parenthesis (used in mathematics to explicit operator priority):  expr 3 * (2 + 1) bash: syntax error near unexpected token `('   How to express operator priority in bash?
119008
Given this string:  SET @text = "&lt;a href=""https://salesforce.stackexchange.com""target=""_blank""&gt;Salesforce&lt;/a&gt; &lt;a href=""https://stackoverflow.com"" target=""_blank""&gt;Everything else&lt;/a&gt;"   And this function:  SET @matching = '\s+(?:[^&gt;]*?\s+)?href="([^"]*)"' SET @output = RegExMatch(@text, @matching, 1)   How can I manage to find and print an arbitrary number of matches in my string? E.g. in above example, I would like to present e.g. a rowset with each URL in each row.
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When and how do we use the different kinds of brackets/parentheses&nbsp;— (){}[]&nbsp;— while writing English (not code)?
33583
How to extract a text part by regexp in linux shell? Lets say, I have a file where in every line is an IP address, but on a different position. What is the simplest way to extract those IP addresses using common unix command-line tools?
7509
I try to write a simple Markdown parser in JavaScript. Therefore I want to check for the [link content][link id] syntax. I use the following code:  data = data.replace( /\[(.*?)\][ ]*\[([0-9]+)\]/g, '&lt;a href="$2"&gt;$1&lt;/a&gt;' );   It works well, but now I want to do this with a RegExp object. So I set up the following bit of code:  var r = new RegExp( '\[(.*?)\][ ]*\[([0-9]+)\]', 'g' ); data = data.replace( r, '&lt;a href="$2"&gt;$1&lt;/a&gt;' );   But it doesn't work. It even says that my regular expression (which works since the first example does a good job) is invalid:     unmatched ) in regular expression   I think it must have to do with some RegExp-object peculiarities I am not aware of. What am I doing wrong and how can the problem be solved?
2773
I have a multi-line equation that I want to have matching sized parentheses. The advice I read online was to use \left( equation \right. \\ left. rest-of-equation \right) . However, this syntax leaves first half of the equation unaware of what is in the second half. For example, if you include a square root term after the break, the second parenthesis will be larger than the opening parenthesis. When you are using the aligned environment to split a long equation this can look somewhat offputting.    Compare the top equation to the bottom one. The parentheses match in size for the bottom equation, but the left hand parentheses for the top one is  noticeably smaller.  Top Code:   \begin{aligned}[t]   \gamma_{\text{u}} + \frac{1}{108}   \left(57\gamma_{\text{er}} \right. &amp;+  38\gamma_{\text{se}}\\ &amp; {}\pm  \left.\sqrt{2601 \gamma_{\text{er}}^2 + 3648  \gamma_{\text{er}}\gamma_{\text{se}} + 1444 \gamma_{\text{se}}^2}  \right)   \end{aligned}   Bottom Code:  \begin{aligned}[t] \gamma_{\text{u}} + \frac{1}{16} \left(9\gamma_{\text{er}}  +  6\gamma_{\text{se}} \pm  \sqrt{49 \gamma_{\text{er}}^2 + 76 \gamma_{\text{er}}\gamma_{\text{se}} + 36 \gamma_{\text{se}}^2} \right) \end{aligned}
4355
For example, this regex  (.*)&lt;FooBar&gt;   will match:  abcde&lt;FooBar&gt;   But how do I get it to match across multiple lines?  abcde fghij&lt;FooBar&gt;
13063
Is it possible to write a regular expression that matches a nested pattern that occurs an unknown number of times? For example, can a regular expression match an opening and closing brace when there are an unknown number of open/close braces nested within the outer braces?  For example:  public MyMethod() {   if (test)   {     // More { }   }    // More { } } // End   Should match:  {   if (test)   {     // More { }   }    // More { } }
47023
Say I have the string "User Name:firstname.surname" contained in a larger string how can I use a regular expression to just get the firstname.surname part?  Every method i have tried returns the string "User Name:firstname.surname" then I have to do a string replace on "User Name:" to an empty string.  Could back references be of use here?  Edit:  The longer string could contain "Account Name: firstname.surname" hence why I want to match the "User Name:" part of the string aswell to just get that value.