silly regexp-replace question: how to delete empty lines

silly regexp-replace question: how to delete empty lines

[leo]

hi there

in a buffer like

  text is here
  and here and
  here

  further text is here

  an the endtext

i want to delete the two empty lines by an regexp-replace.

so i started with _finding_ the lines. that's easy: "^$" is the regexp. but
obviouly (replace-regexp "^$" "ghdfg" nil nil nil) does nothing.;-)

SO in order to delete empty lines (i.e. to replace it with "") i have to
find the empty line _plus_ the linefeed.

so i tried (replace-regexp "^$
" "ghdfg" nil nil nil) where the linefeed was type as C-q C-j. but it
doesn't find anything.

any idea?

thanks, leo

Re: silly regexp-replace question: how to delete empty lines

[Barry Margolin]

regexp-replace is the wrong command.  Use flush-lines.

-- 
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***

Re: silly regexp-replace question: how to delete empty lines

[Sacha Chua]

"leo" <halloleo@noospaam.myrealbox.com> writes:

> i want to delete the two empty lines by an regexp-replace.

You can also use delete-matching-lines... =)

-- 
Sacha Chua <sacha@free.net.ph> - Ateneo CS faculty geekette
interests: emacs, gnu/linux, making computer science education fun
http://sacha.free.net.ph/

Re: silly regexp-replace question: how to delete empty lines

[Peter Lee]

>>>> leo  writes:

    leo> so i tried (replace-regexp "^$ " "ghdfg" nil nil nil) where the
    leo> linefeed was type as C-q C-j. but it doesn't find anything.

The following works.

(replace-regexp "^
" "blank line
" nil nil nil)


---------------------
  text is here
  and here and
  here

  further text is here

  an the endtext

---------------------

Re: silly regexp-replace question: how to delete empty lines

[leo]

thanks peter

now i recall: i guess, the fact that "^[C-j]" works but "^$[C-j]" doesn't,
is kind of a regexp bug/feature in emacs, isn't it?

cheers, leo

"Peter Lee" <pete_lee@swbell.net> wrote in message
news:uy8qhy9lp.fsf@swbell.net...
> >>>> leo  writes:
>
>     leo> so i tried (replace-regexp "^$ " "ghdfg" nil nil nil) where the
>     leo> linefeed was type as C-q C-j. but it doesn't find anything.
>
> The following works.
>
> (replace-regexp "^
> " "blank line
> " nil nil nil)
>
>
> ---------------------
>   text is here
>   and here and
>   here
>
>   further text is here
>
>   an the endtext
>
> ---------------------
>

Re: silly regexp-replace question: how to delete empty lines

[Johan Bockgård]

"leo" <halloleo@noospaam.myrealbox.com> writes:

> now i recall: i guess, the fact that "^[C-j]" works but "^$[C-j]"
> doesn't, is kind of a regexp bug/feature in emacs, isn't it?

    For historical compatibility reasons, `$' can be used only at the
    end of the regular expression, or before `\)' or `\|'.

    For historical compatibility reasons, `^' can be used only at the
    beginning of the regular expression, or after `\(' or `\|'.

(info "(elisp)Regexp Special")

-- 
Johan Bockgård

Re: silly regexp-replace question: how to delete empty lines

[Alan Mackenzie]

Johan Bockgård <bojohan+news@dd.chalmers.se> wrote on Thu, 04 Mar 2004
02:31:27 +0100:
> "leo" <halloleo@noospaam.myrealbox.com> writes:

>> now i recall: i guess, the fact that "^[C-j]" works but "^$[C-j]"
>> doesn't, is kind of a regexp bug/feature in emacs, isn't it?

>     For historical compatibility reasons, `$' can be used only at the
>     end of the regular expression, or before `\)' or `\|'.

>     For historical compatibility reasons, `^' can be used only at the
>     beginning of the regular expression, or after `\(' or `\|'.

> (info "(elisp)Regexp Special")

Yes, it's a pain in the backside.  But leo could write his regexp thus:

"^\\($\\)[C-j]".

> -- 
> Johan Bockgård

-- 
Alan Mackenzie (Munich, Germany)
Email: aacm@muuc.dee; to decode, wherever there is a repeated letter
(like "aa"), remove half of them (leaving, say, "a").

Re: silly regexp-replace question: how to delete empty lines

[Joe Fineman]

M-x query-replace-regexp RET
C-q C-j C-q C-j + RET
C-q C-j RET

is what I would do.
-- 
---  Joe Fineman    jcf@TheWorld.com

||:  Ye shall know the truth, and the truth shall make you free,  :||
||:  but first it shall piss you off beyond belief.               :||

Re: silly regexp-replace question: how to delete empty lines

[Thomas L Roche]

"leo" Wed, 3 Mar 2004 12:11:08 +1100
> in a buffer like

>   text is here
>   and here and
>   here

>   further text is here

>   an the endtext

> i want to delete the two empty lines by an regexp-replace.

Umm ... do you know that you don't need a regexp? You can just do

> M-x replace-string
> C-q C-j C-q C-j
> C-q C-j

That being said,

> M-x replace-regexp
> C-q C-j C-q C-j
> C-q C-j

also works ... but you're not really replacing regexp, just a fixed
string.