I would like to build a regular expression in C# to match question mark except repeated or commented.
For example, if I have a string below
--???
??
asdlfkj --?
asldfjl -?
aslfldkf --?
aslfkvlv --??
?
-?
dklsafdlafjd = ?
, I want to match like below (between * character).
--???
??
asdlfkj --?
asldfjl -*?*
aslfldkf --?
aslfkvlv --??
*?*
-*?*
dklsafdlafjd = *?*
I'm developing SQL binding method using 2 parameters.
The first one is SQL, for example
select * from atable where id = ?.
SQL can have comment so I want ignore them.
The second one is parameter for SQL as Array to match sequentially;
Does anyone have good idea for it?
If you can negate this regex it should work for you:
(\?{2,}|(?<=--)\?)
I don't know what language you're working in, but you should be able to filter by line. Apply this regex as a predicate and either negate it or use a exclude function.
I'll leave those implementation details up to you.
Related
As the title presents above I am trying to reference a capture groups for a regex replace in a postgres query. I have read that the regex_replace does not support using regex capture groups. The regex I am using is
r"(?:[\s\(\)\=\)\,])(username)(?:[\s\(\)\=\)\,])?"gm
The above regex almost does what I need it to but I need to find out how to only allow a match if the capture groups also capture something. There is no situation where a "username" should be matched if it just so happens to be a substring of a word. By ensuring its surrounded by one of the above I can much more confidently ensure its a username.
An example application of the regex would be something like this in postgres (of course I would be doing an update vs a select):
select *, REGEXP_REPLACE(reqcontent,'(?:[\s\(\)\=\)\,])(username)(?:[\s\(\)\=\)\,])?' ,'NEW-VALUE', 'gm') from table where column like '%username%' limit 100;
If there is any more context that can be provided please let me know. I have also found similar posts (postgresql regexp_replace: how to replace captured group with evaluated expression (adding an integer value to capture group)) but that talks more about splicing in values back in and I don't think quite answers my question.
More context and example value(s) for regex work against. The below text may look familiar these are JQL filters in Jira. We are looking to update our usernames and all their occurrences in the table that contains the filter. Below is a few examples of filters. We originally were just doing a find a replace but that doesn't work because we have some usernames that are only two characters and it was matching on non usernames (e.g je (username) would place a new value in where the word project is found which completely malforms the JQL/String resulting in something like proNEW-VALUEct = balh blah)
type = bug AND status not in (Closed, Executed) AND assignee in (test, username)
assignee=username
assignee = username
Definition of Answered:
Regex that will only match on a 'username' if its surrounded by one of the specials
A way to regex/replace that username in a postgres query.
Capturing groups are used to keep the important bits of information matched with a regex.
Use either capturing groups around the string parts you want to stay in the result and use their placeholders in the replacement:
REGEXP_REPLACE(reqcontent,'([\s\(\)\=\)\,])username([\s\(\)\=\)\,])?' ,'\1NEW-VALUE\2', 'gm')
Or use lookarounds:
REGEXP_REPLACE(reqcontent,'(?<=[\s\(\)\=\)\,])(username)(?=[\s\(\)\=\)\,])?' ,'NEW-VALUE', 'gm')
Or, in this case, use word boundaries to ensure you only replace a word when inside special characters:
REGEXP_REPLACE(reqcontent,'\yusername\y' ,'NEW-VALUE', 'g')
I have a csv in following format.
id,mobile
1,02146477474
2,08585377474
3,07646474637
4,02158789566
5,04578599525
I want to add a new column and add just leading 3 numbers to that column (for specific cases and all the others NOT_VALID string). So result should be:
id,number,provider
1,02146477474,021
2,08585377474,085
3,07646474637,NOT_VALID
4,02158789566,021
5,04578599525,NOT_VALID
I can use following regex for replacing that. But I would like to use all possible conversations in one step. Using UpdateRecord processor.
${field.value:replaceFirst('085[0-9]+','085')}
When I use something like this:
${field.value:replaceFirst('085[0-9]+','085'):or(${field.value:replaceFirst('086[0-9]+','086')}`)}
This replaces all with false.
Nifi uses Java regex
As soon, as you are using record processing, this should work for you:
${field.value:replaceFirst('^(021|085)?.*','$1')}
The group () optionally ? catches 021 or 085 at the beginning of string ^
The replacement - $1 - is the first group
PS: The sites like https://regex101.com/ helps to understand regex
I'm currently building a simple search page in Node JS Express and Oracle.
I'd like to show the user a snippet of the matching text (first instance would do) to add a bit context of what the SQL found.
Example:
Search term: 'fish'
Results: Henry really likes going fishing, and once he caug ...
I'm not sure the best way to approach this - I could retrieve the whole block of text and do it in Node JS, but I don't really like the idea of dragging the whole text across to the app, just to get a snippet.
I've been thinking that REGEXP_SUBSTR could be way to do it... But I'm not sure whether I could use a regular expression to retrieve x amount of characters before and after the matching word.
Have I got the right idea or am I going about it in the wrong way?
Thanks
SELECT text
, REGEXP_SUBSTR(LOWER(text), LOWER('fish')) AS potential_snippet
FROM table
WHERE LOWER(text) LIKE LOWER('%fish%');
Try this:
select text
, SUBSTR( TEXT, INSTR(LOWER(TEXT),'fish', 1)-50,100 )
FROM test
WHERE INSTR(LOWER(text),'fish', 1)<>0;
Play with the position and length numbers(50 and 100 in my example) to limit the length of the string.
If you need to extract some context with the help of JavaScript, you can use limiting quantifiers in a regex:
/\b.{0,15}fish.{0,15}\b/i
See demo
Here,
\b - matches at the word boundary (so that the context contains only whole words)
.{0,15} - any characters other than a newline (replace with [\s\S] or [^] if you need to include newlines)
fish - the keyword
The /i modifier enables case-insensitive search.
If you need a dynamic regex creation, use a constructor notation:
RegExp("\\b.{0,15}" + keyword + ".{0,15}\\b", "i");
Also, if you need to find multiple matches, use g modifier alongside the i.
I have a set of strings that I'd like to parse in MATLAB 2012 that all have the following format:
string-int-int-int-int-string
I'd like to pluck out the third integer (the rest are 'don't cares'), but I haven't used MATLAB in ages and need to refresh on regular expressions. I tried using the regular expression '(.*)-(.*)-(.*)-\d-(.*)' but no dice. I did check out the MATLAB regexp page, but wasn't able to figure out how to apply that information to this case.
Anyone know how I might get the desired result? If so, could you explain what the expression you're using is doing to get that result so that others might be able to apply the answer to their unique situation?
Thanks in advance!
str = 'XyzStr-1-2-1000-56789-ILoveStackExchange.txt';
[tok] = regexp(str, '^.+?-.+?-.+?-(\d+?)-.+?-.+?', 'tokens');
tok{:}
ans =
'1000'
Update
Explanation, upon request.
^ - "Anchor", or match beginning of string.
.+? - Wildcard match, one or more, non-greedy.
- - Literal dash/hyphen.
(\d+?) - Digits match, one or more, non-greedy, captured into a token.
^.*?-.*?-.*?-(\d+)-.*?-.*?$
OR
^(?:[^-]*?-){3}(\d+)(?:.*?)$
Group1 now contains your required data
I have the following statement:
Directory.GetFiles(filePath, "A*.pdf")
.Where(file => Regex.IsMatch(Path.GetFileName(file), "[Aa][i-lI-L].*"))
.Skip((pageNum - 1) * pageSize)
.Take(pageSize)
.Select(path => new FileInfo(path))
.ToArray()
My problems is that the above statement also finds the file "Adali.pdf" which it should not - but i cannot figure out why.
The above statement should only select files starting with a, and where the second letter is in the range i-l.
Because it matches Adali taking 3rd and 4th characters (al):
Adali
--
Try using ^ in your regex which allows looking for start of the string (regex cheatsheet):
Regex.IsMatch(..., "^[Aa][i-lI-L].*")
Also I doubt you need asterisk at all.
PS: As a sidenote let me notice that this question doesn't seem to be written that good. You should try debugging this code yourself and particularly you should try checking your regex against your cases without LINQ. I'm sure there is nothing to do here with LINQ (the tag you have in your question), but the issue is about regular expressions (which you didn't mention in tags at all).
You are not anchoring the string. This makes the regex match the al in Adali.pdf.
Change the regex to ^[Aa][i-lI-L].* You can do just ^[Aa][i-lI-L] if you don't need anything besides matching.
You should to do this
var f = Directory.GetFiles(tb_Path.Text, "A*.pdf").Where(file => Regex.IsMatch(Path.GetFileName(file), "[Aa][i-lI-L].pdf")).ToArray();
When you call ".*" Adali accept in Regex