negative-lookahead

问题 I am implementing the following problem in ruby. Here's the pattern that I want : 1234, 1324, 1432, 1423, 2341 and so on i.e. the digits in the four digit number should be between [1-4] and should also be non-repetitive. to make you understand in a simple manner I take a two digit pattern and the solution should be : 12, 21 i.e. the digits should be either 1 or 2 and should be non-repetitive. To make sure that they are non-repetitive I want to use $1 for the condition for my second digit but

问题 I am implementing the following problem in ruby. Here's the pattern that I want : 1234, 1324, 1432, 1423, 2341 and so on i.e. the digits in the four digit number should be between [1-4] and should also be non-repetitive. to make you understand in a simple manner I take a two digit pattern and the solution should be : 12, 21 i.e. the digits should be either 1 or 2 and should be non-repetitive. To make sure that they are non-repetitive I want to use $1 for the condition for my second digit but

问题 I'm trying to get the email addresses from a file using egrep -o -e and having trouble with addresses at the end of a line. Here is my regex: egrep -o -e "[._a-zA-Z0-9]+@[._a-zA-Z0-9]+.[._a-zA-Z0-9]+" ~/myfile.txt I realize this will not catch every variation of an email address, but if the address is at the end of a line this is what I get: user@_12345@myemail.com\ul So I figured I'd try a negative lookahead, but I have no idea how to properly use it. I've read a few things online but I'm

问题 I am trying to search for filenames in a comma-separated list in: text.txt,temp_doc.doc,template.tmpl,empty.zip I use Java's regex implementation. Requirements for output are as follows: Display only filenames and not their respective extensions Exclude files that begin with "temp_" It should look like: text template empty So far I have managed to write more or less satisfactory regex to cope with the first task: [^\\.,]++(?=\\.[^,]*+,?+) I believe to make it comply with the second

问题 I'm doing some regular expression gymnastics. I set myself the task of trying to search for C# code where there is a usage of the as-operator not followed by a null-check within a reasonable amount of space. Now I don't want to parse the C# code. E.g. I want to capture code snippets such as var x1 = x as SimpleRes; var y1 = y as SimpleRes; if(x1.a == y1.a) however, not capture var x1 = x as SimpleRes; var y1 = y as SimpleRes; if(x1 == null) nor for that matter var x1 = x as SimpleRes; var y1

问题 I am trying to replace some value in the query string of the current page using JS. Eg: from category=Old Value to category=New Value . To code looks like this: var sNewValue = 'New Value'; sQueryString = sQueryString.replace(/category=[^&]+&?/, 'category=' + sNewValue); It works fine except for values that have ampersands. Luckily all the ampersands are URL encoded, so I know I should discard the amp; before the & . I think I should use lookaheads, but I don't know how. I tried this regular

问题 I had a regex that matches a P.O. BOX on a given address - /p\.? *o\.? *box/i . But recently my requirement changes to NOT match the P.O. BOX. In other words, the address is valid when P.O. BOX is not found. I was trying to negate that pattern so it matches an address that has no P.O. BOX by using negative lookahead , this is what I came up with so far: /.*(?!p\.? *o\.? *box).*/i , but it is not working right now: https://regex101.com/r/oN1jZ8/1 For example, I try to match the following: this

问题 I'd like to match the word STOP as long as it is does not have a ' anywhere before it - so: STOP 'something - is legal but ' STOP - isn't and neither is something ' something else STOP I've tried using negative lookahead but I can't use quantifiers to allow unlimited whitespace / words 回答1: If you just need to match it without any capturing, I guess something simple as ^[^']*STOP does the trick. 来源： https://stackoverflow.com/questions/35213754/match-word-not-preceded-by-character

问题 This is a follow up to an original question I posted here, but I would appreciate help in expanding its capabilities a bit. I have the following string I am trying to capture from (let's call it output): ltm pool TEST_POOL { Some strings above headers records { baz:1 { ANY STRING HERE session-status enabled } foobar:23 { ALSO ANY STRING HERE session-status enabled } } members { qux:45 { ALSO ANY STRINGS HERE session-status enabled } bash:2 { AND ANY STRING HERE session-status user-disabled }

问题 Using regex with negative lookahead I have to search a text file and identify a partially known line of text that is NOT followed by another partially known line of text. This is a simplified example of the text file: blahblahblah.Name=qwqwqwqwqw abracadabra.Surname=ererererer zxzxzxzxzx.Name=kmkmkmkmkmkm oioioioi.Name=dfdfdfdfdfdf popopopopopopo.Surname=lklklklklklklk In the sample above you can see the pattern where a line with Name should always follow by a line with Surname , but