RegExp: match everything except a certain string

RegExp: match everything except a certain string

[Sven Bretfeld]

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Hello to all

A RegExp beginner's question again. I cannot find a way to search for
a regexp that matches everything except of one certain string. The
problem is:

 author = {somename},
 editor = {},
 title = {sometitle},
 subtitle = {},
 series = {},
 url = {}

I want to find a regexp that matches every line with empty {} except
of the "subtitle line". I've come that far:

^ \<[^s].* = {},*

But this one also excludes the "series line", of course. I was
thinking of \<[^s][^u] but this doesn't work, since, then, the initial
s of "subtitle" is matched again.

What is the syntax for find .* except of the string "subtitle"? I
didn't recognize this in the Lisp info.

Thanks for help

Sven

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Re: RegExp: match everything except a certain string

[Andreas Röhler]

Am Dienstag, 20. November 2007 17:08 schrieb Sven Bretfeld:
> Hello to all
>
> A RegExp beginner's question again. I cannot find a way to search for
> a regexp that matches everything except of one certain string. The
> problem is:
>
>  author = {somename},
>  editor = {},
>  title = {sometitle},
>  subtitle = {},
>  series = {},
>  url = {}
>
> I want to find a regexp that matches every line with empty {} except
> of the "subtitle line". I've come that far:
>
> ^ \<[^s].* = {},*
>
> But this one also excludes the "series line", of course. I was
> thinking of \<[^s][^u] but this doesn't work, since, then, the initial
> s of "subtitle" is matched again.
>
> What is the syntax for find .* except of the string "subtitle"? I
> didn't recognize this in the Lisp info.
>
> Thanks for help
>
> Sven


Got it with:

[^s]?[^u]?[^b]?[^t]?[^i]?[^t]?[^l]?[^e] = {},?$

Please don't ask why :)

Anyway--you will know that and it's not the precise
answer-- it might be useful to point at

M-x shell-command-on-region

grep {} | sed /subtitle/d

as an easy-to-use solution.

Andreas Röhler

Re: RegExp: match everything except a certain string

[Sven Bretfeld]

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Hello Andreas

Andreas Röhler <andreas.roehler@online.de> writes:

>>  author = {somename},
>>  editor = {},
>>  title = {sometitle},
>>  subtitle = {},
>>  series = {},
>>  url = {}
>>
>> I want to find a regexp that matches every line with empty {} except
>> of the "subtitle line". I've come that far:
>>
> Got it with:
>
> [^s]?[^u]?[^b]?[^t]?[^i]?[^t]?[^l]?[^e] = {},?$
>
> Please don't ask why :)

That's working. Thanks. (I don't ask.)

> Anyway--you will know that and it's not the precise
> answer-- it might be useful to point at
>
> M-x shell-command-on-region
>
> grep {} | sed /subtitle/d
>
> as an easy-to-use solution.

It's a good idea to use a sed pipe. But it doesn't matter how much
there is to type, since I need the expression for a function. So I
only have to type it once.

Greetings

Sven

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Re: RegExp: match everything except a certain string

[Lennart Borgman (gmail)]

Sven Bretfeld wrote:
> Hello Andreas
> 
> Andreas Röhler <andreas.roehler@online.de> writes:
> 
>>>  author = {somename},
>>>  editor = {},
>>>  title = {sometitle},
>>>  subtitle = {},
>>>  series = {},
>>>  url = {}
>>>
>>> I want to find a regexp that matches every line with empty {} except
>>> of the "subtitle line". I've come that far:
>>>
>> Got it with:
>>
>> [^s]?[^u]?[^b]?[^t]?[^i]?[^t]?[^l]?[^e] = {},?$
>>
>> Please don't ask why :)
> 
> That's working. Thanks. (I don't ask.)
> 
>> Anyway--you will know that and it's not the precise
>> answer-- it might be useful to point at
>>
>> M-x shell-command-on-region
>>
>> grep {} | sed /subtitle/d
>>
>> as an easy-to-use solution.
> 
> It's a good idea to use a sed pipe. But it doesn't matter how much
> there is to type, since I need the expression for a function. So I
> only have to type it once.

Then it is probably much easier to use two step aproach:

1) use a simpler regexp
2) test if "subtitle" was in the match

Re: RegExp: match everything except a certain string

[Sven Bretfeld]

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Hi Lennart

"Lennart Borgman (gmail)" <lennart.borgman@gmail.com> writes:

>> It's a good idea to use a sed pipe. But it doesn't matter how much
>> there is to type, since I need the expression for a function. So I
>> only have to type it once.
>
> Then it is probably much easier to use two step aproach:
>
> 1) use a simpler regexp
> 2) test if "subtitle" was in the match

This is going to be my first function ever. I will try if I can do it
that way.

Thanks

Sven

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Re: RegExp: match everything except a certain string

[Sven Utcke]

Sven Bretfeld <sven.bretfeld@gmx.ch> writes:

> Hello Andreas
> 
> Andreas Röhler <andreas.roehler@online.de> writes:
> 
> >>  author = {somename},
> >>  editor = {},
> >>  title = {sometitle},
> >>  subtitle = {},
> >>  series = {},
> >>  url = {}
> >>
> >> I want to find a regexp that matches every line with empty {} except
> >> of the "subtitle line". I've come that far:
> >>
> > Got it with:
> >
> > [^s]?[^u]?[^b]?[^t]?[^i]?[^t]?[^l]?[^e] = {},?$
> >
> > Please don't ask why :)
> 
> That's working. Thanks. (I don't ask.)

I haven't followed the original thread, so I might be way of the mark
here, but the above would of course not find "title = {}" either (as
well as quite a few less likely variations).

If using external programs is an option,

grep '\{\}' | grep -v subtitle

would do what you are looking for...

Sven
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Re: RegExp: match everything except a certain string

[Malte Spiess]

Sven Utcke <utcke+news@informatik.uni-hamburg.de> writes:

> Sven Bretfeld <sven.bretfeld@gmx.ch> writes:
>
>> Hello Andreas
>> 
>> Andreas Röhler <andreas.roehler@online.de> writes:
>> 
>> >>  author = {somename},
>> >>  editor = {},
>> >>  title = {sometitle},
>> >>  subtitle = {},
>> >>  series = {},
>> >>  url = {}
>> >>
>> >> I want to find a regexp that matches every line with empty {} except
>> >> of the "subtitle line". I've come that far:
>> >>
>> > Got it with:
>> >
>> > [^s]?[^u]?[^b]?[^t]?[^i]?[^t]?[^l]?[^e] = {},?$
>> >
>> > Please don't ask why :)
>> 
>> That's working. Thanks. (I don't ask.)
>
> I haven't followed the original thread, so I might be way of the mark
> here, but the above would of course not find "title = {}" either (as
> well as quite a few less likely variations).

Yeah, you are right, the [^s]? (and so on) seem pretty useless because
the empty string matches them. The whole expression can be reduced to

[^e] = {},?$

which means that any string that does not end with an "e" should be
matched... (it does that here)

Greetings
Malte

Re: RegExp: match everything except a certain string

[Stefan Monnier]

> [^s]?[^u]?[^b]?[^t]?[^i]?[^t]?[^l]?[^e] = {},?$

Nice try, but no cigar ;-)

How 'bout something like:

"\\(?:[^s]\\|s\\(?:[^u]\\|u\\(?:[^b]\\|b\\(?:[^t]\\|t\\(?:[^i]\\|i\\(?:[^t]\\|t\\(?:[^l]\\|l\\(?:[^e]\\|e[^\t\n ]\\)\\)\\)\\)\\)\\)\\)\\)"

this is just a starting point, because even if you have "subtitle" in
your buffer the "title" part doesn't match "subtitle", so
a regexp-search may find "title" as a match: negation in regexp search
is pretty tricky.


        Stefan



(defun regexp-not-in (words endchars &optional prefix)
  "Return a regexp that matches anything other than words in WORDS.
ENDCHARS is a list containing the chars that can appear after a word."
  ;; `prefix' is only used internally.
  (if prefix (setq words (all-completions prefix words)) (setq prefix ""))
  (let* ((pos (length prefix))
         (empty (when (member prefix words)
                  (setq words (remove prefix words)) t))
         (chars (delete-dups (mapcar (lambda (word) (aref word pos)) words)))
         (chars-re (regexp-opt-charset (if empty (nconc chars endchars) chars)))
         (nonchars-re (concat "[^" (substring chars-re 1 -1) "]")))
    (cond
     ((and empty (null endchars))
      ;; If there are no termination chars, then we have to simply disallow
      ;; this match altogether.
      "\\`")
     ((null chars) nonchars-re)
     (t
      (concat "\\(?:" nonchars-re
              "\\|"
              (mapconcat (lambda (char)
                           (setq char (string char))
                           (concat char
                                   (regexp-not-in words endchars
                                                  (concat prefix char))))
                         chars
                         "\\|")
              "\\)")))))