Re: Delete a string possibly over two lines

[tybalt89]

#!/usr/bin/perl

# http://perlmonks.org/?node_id=1208527

use strict;
use warnings;

local $/ = '}';    # use } as line terminator...

while(<DATA>)
  {
  s/.*\K\{ Name.*\}//s;
  print;
  }

__DATA__
{ Name 1.2.3 xxxx xxxxx}

where xxxx and xxxxx could be a-z, 0-9 or : (a single colon).

There could be one or more spaces after { and before the } and there c
+ould be one or more spaces between the groups in the string. Also the
+ string could be split over two lines like

{ Name 1.2.3
xxxx xxxxx }

{ Name 1.2.
3 xxxx xxxxx}

{ Name 1.2.3 xxxx
xxxxx }.

So it could be split at a space or after a dot. There could be one or 
+more spaces at the end of the split line before the newline like this

{ Name 1.2.3\ \ \ \
xxxx }

where I use \ to denote a space.

My question is how do I get rid of all these strings in a file. I'm us
+ing Perl under Windows 10 if that helps.

Thanks.

Outputs:

where xxxx and xxxxx could be a-z, 0-9 or : (a single colon).

There could be one or more spaces after { and before the } and there c
+ould be one or more spaces between the groups in the string. Also the
+ string could be split over two lines like





.

So it could be split at a space or after a dot. There could be one or 
+more spaces at the end of the split line before the newline like this



where I use \ to denote a space.

My question is how do I get rid of all these strings in a file. I'm us
+ing Perl under Windows 10 if that helps.

Thanks.

[AnomalousMonk]

s/.*\K\{ Name.*\}//s;

I don't understand the purpose of the  .*\K sub-expression in this substitution. Is it perhaps intended as a defensive measure against nested  { ... } groups? I suppose the thing to do is play around with it a bit, but I don't have time ATM. Could you please comment on this?

[tybalt89]

Yes, it is defense against nested (or only "first half of") expressions.

[texuser]

Thank you for your quick response and code. It get rids of the string but leaves things like { } after it runs. Is there a way to remove the enclosing brackets as well? I probably wasn't clear that I wanted to delete them as well.

Also if there are other strings with similar patterns in the file, like { AnotherName 4.5.6 xxx xxxx}, do I have to write separate perl scripts or can I do it all in one script?

Thanks again.

[AnomalousMonk]

... if there are other strings with similar patterns in the file, like { AnotherName 4.5.6 xxx xxxx}, do I have to write separate perl scripts ...

Ah, what's in a name? A set of names could be defined as
    my $name = qr{ \b (?: Phil | Bob | Hal) \b }xms;
and used in tybalt89's substitution statement as
    s/.*\K\{ $name.*\}//s;
(untested). However, you have to define what constitutes a "name".

Update 1: Similarly, a "dotted decimal" regex could be defined that would match any dotted decimal (with optional embedded whitespace), some subset, or... For instance (also untested):

my $dotted_decimal = qr{
  (?<! \d) \d+ (?: \s* [.] \s* \d+){2,3} (?! \d)
  }xms;

This can, I think, be broken over arbitrary lines. Again, you must decide what is needed in your application.

Update 2: I've changed the  $dotted_decimal definition above to conform to the expanded specification examples provided here: counted quantifier  {2} changed to  {2,3} instead (and it's still untested).

[tybalt89]

No, it does not leave { } in the output. Did you mis-copy it?

Looks like you are changing the spec. Please give exact definition of "other strings with similar patterns".

[texuser]

I'm new to perl so I may have made a mistake. Here are two examples of the strings I want to delete

{ Programa 1.2.3 64-bit 2dat: }

{ Programb 10.1.2.3 64-bit 1dat: }

Also sometimes there are no spaces between the braces like {Programa 1.2.3 64-bit 2dat:}, { Programa 1.2.3 64-bit 2dat:} and {Programa 1.2.3 64-bit 2dat: }. Does this make a difference to the code?

It would be good to get rid of both strings in one script. I'm using Perl version 5.24.1.

Update: After doing some reading, I have now tried s/.*\K\{\s*Name.*\}//s; and that seems to work with spaces/no spaces with the {}. I still don't know how to use one script to remove two or more strings like { Programa 1.2.3 64-bit 2dat: } and { Programb 10.1.2.3 64-bit 1dat: }.

Thanks.