I am trying to craft some regex that can match all of the following strings (no more, no less):
ftp
ftps
sftp
ftpes
The closest I have gotten is: ^ftps?$ but as you can tell that only matches the top two. How can I match all of the ones listed? I am aware that I can use something like ^(ftp|ftps|sftp|ftpes)$ but I wanted to save as much space as possible (my actual application is much much larger than this so space saving is more necessary. I used the ftp example for visual appeal).
I am using this in a bash 3.2.57(1)-release if-statement.
I suggest this extended regex:
^(ftpe?s|s?ftp)$
ftpe?s: one e is optional
s?ftp: one s is optional
See: The Stack Overflow Regular Expressions FAQ
A variation on an extended regex would be:
^(s?ftp|^ftp(s|es)?)$
Here:
(^s?ftp| zero or one 's' followed by ftp at the beginning
or
ftp followed by (s|es)?$ zero or one 's' or 'es' after.
Let me know if you have further questions.
Related
I'm trying to see if its possible to extend an existing arbitrary regex by prepending or appending another regex to match within matches.
Take the following example:
The original regex is cat|car|bat so matching output is
cat
car
bat
I want to add to this regex and output only matches that start with 'ca',
cat
car
I specifically don't want to interpret a whole regex, which could be quite a long operation and then change its internal content to match produce the output as in:
^ca[tr]
or run the original regex and then the second one over the results. I'm taking the original regex as an argument in python but want to 'prefilter' the matches by adding the additional code.
This is probably a slight abuse of regex, but I'm still interested if it's possible. I have tried what I know of subgroups and the following examples but they're not giving me what I need.
Things I've tried:
^ca(cat|car|bat)
(?<=ca(cat|car|bat))
(?<=^ca(cat|car|bat))
It may not be possible but I'm interested in what any regex gurus think. I'm also interested if there is some way of doing this positionally if the length of the initial output is known.
A slightly more realistic example of the inital query might be [a-z]{4} but if I create (?<=^ca([a-z]{4})) it matches against 6 letter strings starting with ca, not 4 letter.
Thanks for any solutions and/or opinions on it.
EDIT: See solution including #Nick's contribution below. The tool I was testing this with (exrex) seems to have a slight bug that, following the examples given, would create matches 6 characters long.
You were not far off with what you tried, only you don't need a lookbehind, but rather a lookahead assertion, and a parenthesis was misplaced. The right thing is: Put the original pattern in parentheses, and prepend (?=ca):
(?=ca)(cat|car|bat)
(?=ca)([a-z]{4})
In the second example (without | alternative), the parentheses around the original pattern wouldn't be required.
Ok, thanks to #Armali I've come to the conclusion that (?=ca)(^[a-z]{4}$) works (see https://regexr.com/3f4vo). However, I'm trying this with the great exrex tool to attempt to produce matching strings, and it's producing matches that are 6 characters long rather than 4. This may be a limitation of exrex rather than the regex, which seems to work in other cases.
See #Nick's comment.
I've also raised an issue on the exrex GitHub for this.
I need a help with mass search and replace using regex.
I have a longer strings where I need to look for any number and particular string - e.g. 321BS and I need to replace just the text string that I was looking for. So I need to look for BS in "gf test test2 321BS test" (the pattern is always the same just the position differs) and change just BS.
Can you please help me to find particular regex for this?
Update: I need t keep the number and change just the text string. I will be doing this notepad++. However I need a general funcion for this if possible. I am a rookie in regex. Moreover, is it possible to do it in Trados SDL Studio? Or how am i able to do it in excel file in bulk?
Thank you very much!
Your question is a bit vague, however, as I understand it you want to match any digits followed by BS, ie 123BS. You want to keep 123 but replace BS?
Regex: (\d+)BS matches 123BS
In notepad++ you can:
match (\d+)BS
replace \1NEWTEXT
This will replace 123BS with 123NEWTXT.
\1 will substitue the capture group (\d+). (which matches 1 or more digits.
You could do this in Trados Studio using an app. The SDLXLIFF Toolkit may be the most appropriate for you. The advantage over Notepad++ is that it's controlled and will only affect the translatable text and not anything that might break the integrity of the file if you make a mistake. You can also handle multiple files, or even multiple Trados Studio projects in one go.
The syntax would be very similar to the suggestion above... you would:
match (\d+)BS
replace $1NEWTEXT
This question already has an answer here:
Learning Regular Expressions [closed]
(1 answer)
Closed 6 years ago.
I am trying to make a regular expression capture any words in the specific line after the word Attachment:
This question is for work, so it is not a homework or test question. I took the paragraph below as an example from www.regular-expressions.info. I did not major in computers but Psychology so this is completely foreign to me. I've read the manuals for the last two days, and because this is going over my head, I don't know how to begin.
I have a task which involves me linking the attachments to a specific file with the same name saved in a folder (at least 500 attachments) on Adobe PDF. What I did before was to manually select the words and link it to a specific file in a folder, but it is tedious to do when they can go up to 500 attachments.
I was aware of an application plug-in called EVERMAP that you can download for Adobe to automatically link specific words to a specific file in a folder. However, it requires me to use regular expressions which again, I don't know how to use.
I will bold the words I want to capture in the paragraph below.
The repetition operator manual expand the match as far as they, and only come back if they must to satisfy the remainder.
Attachment: The repetition operator manual
The asterisk or star tells the engine to attempt to match the preceding token zero or more times. The plus tells the engine to attempt to match the preceding token once or more.
Attachment: Asterisk and stars engine
Attachment: (.+) should work in your case unless there are other exceptions to this rule. The regex simply tells the parser to capture 1 or more character after the word Attachment:. See here for the sample
Like #Kevin said, the Regex is simple. Use Attachment: (.+).
Maybe you are confused on how to use Regex. I don't know about the Evermap plugin, but you can copy all the text from the PDF to Sublime Text (text editor to open .txt but with a lot of features) and do Regex part there. And then, since you are not a programmer, you should remove other irrelevant data. So the Regex will be:
`^\s*Attachment:\s*(.+)$|^(?!Attachment:).+$`
And replace it with:
`\1`
\1 is a variable containing group value caught in ()
In Sublime Text find Find and Replace, then apply the Regex there. Don't forget to turn on the Regex mode.
I'm new to regex. I need to find instances of example.com in an .SQL file in Notepad++ without those instances being part of subdomain.example.com(edited)
From this answer, I've tried using ^((?!subdomain))\.example\.com$, but this does not work.
I tested this in Notepad++ and # https://regex101.com/r/kS1nQ4/1 but it doesn't work.
Help appreciated.
Simple
^example\.com$
with g,m,i switches will work for you.
https://regex101.com/r/sJ5fE9/1
If the matching should be done somewhere in the middle of the string you can use negative look behind to check that there is no dot before:
(?<!\.)example\.com
https://regex101.com/r/sJ5fE9/2
Without access to example text, it's a bit hard to guess what you really need, but the regular expression
(^|\s)example\.com\>
will find example.com where it is preceded by nothing or by whitespace, and followed by a word boundary. (You could still get a false match on example.com.pk because the period is a word boundary. Provide better examples in your question if you want better answers.)
If you specifically want to use a lookaround, the neative lookahead you used (as the name implies) specifies what the regex should not match at this point. So (?!subdomain\.)example trivially matches always, because example is not subdomain. -- the negative lookahead can't not be true.
You might be better served by a lookbehind:
(?<!subdomain\.)example\.com
Demo: https://regex101.com/r/kS1nQ4/3
Here's a solution that takes into account the protocols/prefixes,
/^(www\.)?(http:\/\/www\.)?(https:\/\/www\.)?example\.com$/
Short version:
How can I get a regex that matches a#a.aaaa but not a#a.aaaaa using CAtlRegExp ?
Long version:
I'm using CAtlRegExp http://msdn.microsoft.com/en-us/library/k3zs4axe(VS.80).aspx to try to match email addresses. I want to use the regex
^[A-Z0-9._%+-]+#(?:[A-Z0-9-]+\.)+[A-Z]{2,4}$
extracted from here.
But the syntax that CAtlRegExp accepts is different than the one used there. This regex returns the error REPARSE_ERROR_BRACKET_EXPECTED, you can check for yourself using this app: http://www.codeproject.com/KB/string/mfcregex.aspx
Using said app, I created this regex:
^[a-zA-Z0-9\._%\+\-]+#([a-zA-Z0-9-]+\.)+[a-zA-Z]$
But the problem is this matches a#a.aaaaa as valid, I need it to match 4 characters maximum for the op-level domain.
So, how can I get a regex that matches a#a.aaaa but not a#a.aaaaa ?
Try: ^[a-zA-Z0-9\._%\+\-]+#([a-zA-Z0-9-]+\.)+\c\c\c?\c?$
This expression replaces the [A-Z]{2,4} sequence which CAtlRegExp doesn't support with \c\c\c?\c?
\c serves as an abbreviation of [a-zA-Z]. The question marks after the 3rd and 4th \c's indicate they can match either zero or one characters. As a result, this portion of the expression matches 2, 3 or 4 characters, but neither more nor less.
You are trying to match email addresses, a very widely used critical element of internet communication.
To which I would say that this job is best done with the most widely used most correct regex.
Since email address format rules are described by RFC822, it seems useful to do internet searches for something like "RFC822 email regex".
For Perl the answer seems to be easy: use Mail::RFC822::Address: regexp-based address validation
RFC 822 Email Address Parser in PHP
Thus, to achieve the most correct handling of email addresses, one should either locate the most precise regex that there is out somewhere for the particular toolkit (ATL in your case) or - in case there's no suitable existing regex yet - adapt a very precise regex of another toolkit (Perl above seems to be a very complete albeit difficult candidate).
If you're trying to match a specific sub part of email addresses (as seems to be the case given your question), then it probably still makes sense to start with the most up-to-date/correct/universal regex and specifically limit it to the parts that you require.
Perhaps I stated the obvious, but I hope it helped.