In vim I would like to use regex to highlight each line that ends with a letter, that is preceeded by neither // nor :. I tried the following
syn match systemverilogNoSemi "\(.*\(//\|:\).*\)\#!\&.*[a-zA-Z0-9_]$" oneline
This worked very good on comments, but did not work on lines containing colon.
Any idea why?
Because with this regex vim can choose any point for starting match for your regular expression. Obviously it chooses the point where first concat matches (i.e. does not have // or :). These things are normally done by using either
\v^%(%(\/\/|\:)#!.)*\w$
(removed first concat and the branch itself, changed .* to %(%(\/\/|\:)#!.)*; replaced collection with equivalent \w; added anchor pointing to the start of line): if you need to match the whole line. Or negative look-behind if you need to match only the last character. You can also just add anchor to the first concat of your variant (you should remove trailing .* from the first concat as it is useless, and the branch symbol for the same reason).
Note: I have no idea why your regex worked for comments. It does not work with comments the way you need it in all cases I checked.
does this work for you?
^\(\(//\|:\)\#<!.\)*[a-zA-Z0-9_]$
Related
I need to match any string that has certain characteristics, but I think enabling the /m flag is breaking the functionality.
What I know:
The string will start and end with quotation marks.
The string will have the following words. "the", "fox", and "lazy".
The string may have a line break in the middle.
The string will never have an at sign (used in the regex statement)
My problem is, if I have the string twice in a single block of text, it returns once, matching everything between the first quote mark and last quote mark with the required words in-between.
Here is my regex:
/^"the[^#]*fox[^#]*lazy[^#]*"$/gim
And a Regex101 example.
Here is my understanding of the statement. Match where the string starts with "the and there is the word fox and lazy (in that order) somewhere before the string ends with ". Also ignore newlines and case-sensitivity.
The most common answer to limiting is (.*?) But it doesn't work with new lines. And putting [^#?]* doesn't work because it adds the ? to the list of things to ignore.
So how can I keep the "match everything until ___" from skipping until the last instance while still being able to ignore newlines?
This is not a duplicate of anything else I can find because this deals with multi-line matching, and those don't.
In your case, all your quantifiers need to be non-greedy so you can just use the flag ungreedy: U.
/^"the[^#]*fox[^#]*lazy[^#]*"$/gimU
Example on Regex101.
The answer, which was figured out while typing up this question, may seem ridiculously obvious.
Put the ? after the *, not inside the brackets. Parenthesis and Brackets are not analogous, and the ? should be relative to the *.
Corrected regex:
/^"the[^#]*?fox[^#]*?lazy[^#]*?"$/gim
Example from Regex101.
The long and the short of this is:
Non-greedy, multi-line matching can be achieved with [^#]*?
(substituting # for something you don't want to match)
When one tries to remove some characters from the start of a line and the anchored pattern can be found again after the first replace, it will be removed again.
For a very simple example given the input 012345, search pattern ^. and empty replacement, Notepad++ will remove the whole line when using replace all. This is most likely due to the case, that the cursor is still at the start of the line after the first replace and thus matches the ^ anchor again.
How can one ensure that only the actual first character is removed (in my case the expected output would be 12345)?
You can see my workaround in my answer, but maybe there is another nice trick to achieve it.
One can match the rest of the line, capture the match into a group and then use this group as replacement. The pattern in the question could be adjusted to ^.(.*) and be replaced by $1.
This will force the cursor to move forward in the string, so the ^ anchor can't match again.
Another workaround could be finding:
^.(.)?
and replacing it with:
\1
I'm sure this is a subject of a bug report but couldn't find it as of now. In N++:
Anchors are buggy
By Replace All functionality, replacements are supposed to not be a subject to re-matching. But they are, when replacement strings are invisible / zero-length characters.
Take care of them.
I've got a practical application for a vim regex where I'd like to remove numbers from the end of file location links. For example, if the developer is sloppy and just adds files and doesn't reuse file locations, you'll end up with something awful like this:
PATH_TO_MY_FILES>
PATH_TO_MY_FILES1>
...
PATH_TO_MY_FILES22>
PATH_TO_MY_FILES_ELSEWHERE>
PATH_TO_MY_FILES_ELSEWHERE1>
...
So all I want to do is to S&R and replace PATH_TO_MY_FILES*\d+ with PATH_TO_MY_FILES* using regex. Obviously I am not doing it quite right, so I was hoping someone here could not spoon feed the answer necessarily, but throw a regex buzzword my way to get me on track.
Here's what I have tried:
:%s\(PATH_TO_MY_FILES\w*\)\(\d+\)>:gc
But this doesn't work, i.e. if I just do a vim search on that, it doesn't find anything. However, if I use this:
:%s\(PATH_TO_MY_FILES\w*\)\(\d\)>:gc
It will match the string, but the grouping is off, as expected. For example, the string PATH_TO_MY_FILES22 will be grouped as (PATH_TO_MY_FILES2)(2), presumably because the \d only matches the 2, and the \w match includes the first 2.
Question 1: Why doesn't \d+ work?
If I go ahead and use the second string (which is wrong), Vim appears to find a match (even though the grouping is wrong), but then does the replacement incorrectly.
For example, given that we know the \d will only match the last number in the string, I would expect PATH_TO_MY_FILES22> to get replaced with PATH_TO_MY_FILES2>. However, instead it replaces it with this:
PATH_TO_MY_FILES2PATH_TO_MY_FILES22>gt
So basically, it looks like it finds PATH_TO_MY_FILES22>, but then replaces only the & with group 1, which is PATH_TO_MY_FILES2.
I tried another regex at Regexr.com to see how it would interpret my grouping, and it looked correct, but maybe a hack around my lack of regex understanding:
(PATH_TO_\D*)(\d*)>
This correctly broke my target string into the PATH part and the entire number, so I was happy. But then when I used this in Vim, it found the match, but still replaced only the &.
Question 2: Why is Vim only replacing the &?
Answer 1:
You need to escape the + or it will be taken literally. For example \d\+ works correctly.
Answer 2:
An unescaped & in the replacement portion of a substitution means "the entire matched text". You need to escape it if you want a literal ampersand.
Quite a simple one in theory but can't quite get it!
I want a regex in ant which matches anything as long as it has a slash on the end.
Below is what I expect to work
<regexp id="slash.end.pattern" pattern="*/"/>
However this throws back
java.util.regex.PatternSyntaxException: Dangling meta character '*' near index 0
*/
^
I have also tried escaping this to \*, but that matches a literal *.
Any help appreciated!
Your original regex pattern didn't work because * is a special character in regex that is only used to quantify other characters.
The pattern (.)*/$, which you mentioned in your comment, will match any string of characters not containing newlines, however it uses a possibly unnecessary capturing group. .*/$ should work just as well.
If you need to match newline characters, the dot . won't be enough. You could try something like [\s\S]*/$
On that note, it should be mentioned that you might not want to use $ in this pattern. Suppose you have the following string:
abc/def/
Should this be evaluated as two matches, abc/ and def/? Or is it a single match containing the whole thing? Your current approach creates a single match. If instead you would like to search for strings of characters and then stop the match as soon as a / is found, you could use something like this: [\s\S]*?/.
Let's say I have a regular expression that works correctly to find all of the URLs in a text file:
(http://)([a-zA-Z0-9\/\.])*
If what I want is not the URLs but the inverse - all other text except the URLs - is there an easy modification to make to get this?
You could simply search and replace everything that matches the regular expression with an empty string, e.g. in Perl s/(http:\/\/)([a-zA-Z0-9\/\.])*//g
This would give you everything in the original text, except those substrings that match the regular expression.
If for some reason you need a regex-only solution, try this:
((?<=http://[a-zA-Z0-9\/\.#?/%]+(?=[^a-zA-Z0-9\/\.#?/%]))|\A(?!http://[a-zA-Z0-9\/\.#?/%])).+?((?=http://[a-zA-Z0-9\/\.#?/%])|\Z)
I expanded the set of of URL characters a little ([a-zA-Z0-9\/\.#?/%]) to include a few important ones, but this is by no means meant to be exact or exhaustive.
The regex is a bit of a monster, so I'll try to break it down:
(?<=http://[a-zA-Z0-9\/\.#?/%]+(?=[^a-zA-Z0-9\/\.#?/%])
The first potion matches the end of a URL. http://[a-zA-Z0-9\/\.#?/%]+ matches the URL itself, while (?=[^a-zA-Z0-9\/\.#?/%]) asserts that the URL must be followed by a non-URL character so that we are sure we are at the end. A lookahead is used so that the non-URL character is sought but not captured. The whole thing is wrapped in a lookbehind (?<=...) to look for it as the boundary of the match, again without capturing that portion.
We also want to match a non-URL at the beginning of the file. \A(?!http://[a-zA-Z0-9\/\.#?/%]) matches the beginning of the file (\A), followed by a negative lookahead to make sure there's not a URL lurking at the start of the file. (This URL check is simpler than the first one because we only need the beginning of the URL, not the whole thing.)
Both of those checks are put in parenthesis and OR'd together with the | character. After that, .+? matches the string we are trying to capture.
Then we come to ((?=http://[a-zA-Z0-9\/\.#?/%])|\Z). Here, we check for the beginning of a URL, once again with (?=http://[a-zA-Z0-9\/\.#?/%]). The end of the file is also a pretty good sign that we've reached the end of our match, so we should look for that, too, using \Z. Similarly to a first big group, we wrap it in parenthesis and OR the two possibilities together.
The | symbol requires the parenthesis because its precedence is very low, so you have to explicitly state the boundaries of the OR.
This regex relies heavily on zero-width assertions (the \A and \Z anchors, and the lookaround groups). You should always understand a regex before you use it for anything serious or permanent (otherwise you might catch a case of perl), so you might want to check out Start of String and End of String Anchors and Lookahead and Lookbehind Zero-Width Assertions.
Corrections welcome, of course!
If I understand the question correctly, you can use search/replace...just wildcard around your expression and then substitute the first and last parts.
s/^(.*)(your regex here)(.*)$/$1$3/
im not sure if this will work exactly as you intend but it might help:
Whatever you place in the brackets [] will be matched against. If you put ^ within the bracket, i.e [^a-zA-Z0-9/.] it will match everything except what is in the brackets.
http://www.regular-expressions.info/