Hi Chris Daniel,

This thread sounds incredibly similar to Regular Expression to replace & in XML by denzil_cactus, are they related?

Regards,
-- Hauke D

> are they related?

That's obviously the same person.

IIRC it's official policy here to block multiple accounts.

update

... or at least strike voting rights (?)

Cheers Rolf
_{(addicted to the Perl Programming Language and ☆☆☆☆ :)
Je suis Charlie!}

If you're so certain that the two accounts are run by the same person, maybe you care to share the additional deep knowledge you have?

Another, very trivial explanation could be that two different persons got the same homework tasks, or that this task has become a common hiring question, or that some common "data provider" (say, Wikipedia, or Amazon or Wordpress) produces such broken HTML since the release of a new version and that they are trying to solve the same problem.

Hi LanX,

IIRC it's official policy here to block multiple accounts.

Not sure if it's up-to-date, but Site Rules Governing User Accounts appears to document the policy (multiple accounts are ok but only one can vote).

Regards,
-- Hauke D

echo 'one & two &# three &#3 four &#38 five & six' | perl -pe 's/&
+(#(3(8(;\K)?)?)?)?//g'
[download]

hehehe

Oops. Misread the output.

Nice!

And, for windows, change all the single quotes to doubles.

C:\>echo "one & two &# three &#3 four &#38 five & six" | perl -pe 
+"s/&(#(3(8(;\K)?)?)?)?//;"
"one  two &# three &#3 four &#38 five & six"
[download]




Spirit of the Monastery

Hello Chris Daniel, and welcome to the Monastery!

Please note that your requirement as stated is self-contradictory. I assume you don’t want to remove the entity &#38. In which case, you can use a negative lookahead assertion to ensure that the entity to be removed is not immediately followed by another digit:

20:54 >perl -wE "my $x = '<Remarks>1 SW PLT SLAC 6 PCS &#3</Remarks>';
+ $x =~ s/&#\d(?!\d)//g; say $x;"
<Remarks>1 SW PLT SLAC 6 PCS </Remarks>

20:54 >perl -wE "my $x = '<Remarks>1 SW PLT SLAC 6 PCS &#38</Remarks>'
+; $x =~ s/&#\d(?!\d)//g; say $x;"
<Remarks>1 SW PLT SLAC 6 PCS &#38</Remarks>

20:54 >
[download]

See “Lookaround Assertions” in perlre#Extended-Patterns.

Hope that helps,

I basically want to replace the string &,&#,&#3,&#38 to blank, but it should not replace &

Please explain.

Update: added code tags because some characters were dropped from &#38 rendering the post difficult to understand.

I am looking like if & is not followed by #38; then replace the & to blank.

If a line consist of & or &# or &#3 or &#38 should be replaced to blan
+k but & should not be affected.
[download]

Note: File is 200+ MB so thinking to apply sed command.

If I understand you correctly, the important difference is the semi-colon: you want to replace &#38, but not if it is followed by a semi-colon (i.e. you don't want to replace &). The poor formatting in your post made it difficult to understand that.

The easy solution is to use a negative look-ahead, as already suggested in other posts, but I doubt that sed supports look-ahead assertions (it may depend which version).

Besides, even for a 200 MB file, this should not be a problem in Perl. Last time I compared the performance of Perl and sed, I did not find a really significant performance difference between them, but, again, this may depend on the implementation of the sed version you're using.

See Using Look-ahead and Look-behind

NB: this won't be xml aware!

update

Look ahead not look behind, Sorry I confused perspectives. ;)

Hello LanX,

I missed the semicolon because of the question’s formatting, but I don’t think you need a look-behind to handle it; a simple look-ahead seems to be enough:

21:08 >perl -wE "my $x = '<Remarks>1 SW PLT SLAC 6 PCS &#3;</Remarks>'
+; $x =~ s/&#\d(?!\d);?//g; say $x;"
<Remarks>1 SW PLT SLAC 6 PCS </Remarks>

21:08 >perl -wE "my $x = '<Remarks>1 SW PLT SLAC 6 PCS &#38;</Remarks>
+'; $x =~ s/&#\d(?!\d);?//g; say $x;"
<Remarks>1 SW PLT SLAC 6 PCS &#38;</Remarks>

21:09 >perl -wE "my $x = '<Remarks>1 SW PLT SLAC 6 PCS &#3</Remarks>';
+ $x =~ s/&#\d(?!\d);?//g; say $x;"
<Remarks>1 SW PLT SLAC 6 PCS </Remarks>

21:09 >
[download]

Or am I still missing something?

Athanasius <°(((>< contra mundum

Iustus alius egestas vitae, eros Piratica,

No I already corrected in the mean time.

Only work and no play makes LanX a dull boy 

Cheers Rolf
_{(addicted to the Perl Programming Language and ☆☆☆☆ :)
Je suis Charlie!}

This looks perfect. But I need to remove the entities without opening the file. Using the unix sed command would be great... Any other suggestion to replace the string without opening the file would be great...

> I basically want to replace the string &,&#,&#3,&#38 to blank, but it should not replace &

This meets your "requirements" and is IMHO easier to understand and more intuitive than tybald89's solution

  DB<19> p $test
&,&#,&#3,&#38,&#38;&,&#,&#3,&#38,&#38;
  DB<20> p $test =~ s/(&#\d+;)|&#?\d*/$1/gr
,,,,&#38;,,,,&#38;
[download]

The trick is to first match correct entities and leave them unchanged by replacing them with themselves.

Incorrect entities are then found by backtracking and replaced with an empty $1.

Please handle this with care, I'm not sure if your requirements didn't miss edge cases.

NB: yes, it will also replace &38 without #

  DB<22> p ',&38,' =~ s/(&#\d+;)|&#?\d*/$1/gr
,,
[download]

otherwise you can add other or-conditions to exclude this case.

update

replaced s/(&#?\d*;)|... with s/(&#\d+;)|