Search and replace text contents of a tag

Question

I am trying to specifically to pad out the /'s in an a tag's text.

1234/1234/ABCDE => 1234 / 1234 / ABCDE

In context; if I have an a tag:

<a href="http://www.domain.com/path/to/page.html"&gt;12 34/1234A/BC DEFG</a>

I would like to get:

<a href="http://www.domain.com/path/to/page.html"&gt;12 34 / 1234A / BC DEFG</a>

Answer 1

What language? In Perl, try s/\// \/ /g.

Answer 2

This isn't really the kind of thing regular expressions are good at doing. You'll probably be better off using an HTML or XML parser - it creates a tree of nodes out of the document, and then you can just step through all the text nodes that are inside of tags and add spaces as needed.

Answer 3

This Regex should do the trick:

(\s*/\s*(?=[^<>]+<))

It will only replace the '/' within tags and not URLs.

In C#:

 myHtml = Regex.Replace(myHtml, @"(\s*/\s*(?=[^<>]+<))", " / ");

In Perl:

$myHtml =~ s!(\s*/\s*(?=[^<>]+<))! / !g;

In JavaScript:

myHtml = myHtml.replace(/(\s*\/\s*(?=[^<>]+<))/g, " / ");

Note:

in these examples, the whole document must be loaded in the myHtml string.
If you work on a single line at a time, it obviously won't work if there are newlines inside the tags or in-between tag pairs.

Answer 4

I think we're lacking a bit of context here. Is the data HTML, XML, or just fragments of text with tags?

If it is HTML or XML, as mentioned often, regexps are not safe, unless you control exactly the format of the data, and you know that you will always control it. And you document it.

I would use an appropriate parser if I were you. If you have Perl and XML::Twig installed, the following one-liner will do:

perl -MXML::Twig -e'XML::Twig->parse( keep_spaces => 1, "my_file.xml")->subs_text( "/", " / ")->print'

If you're dealing with well-formed XML with no comments and no CDATA sections, then a more efficient way would be to use PYX (you need to install XML::PYX):

pyx my_file.xml | perl -p -e's{/}{ / }g if m{-}' | pyxw

Answer 5

If you need to, you could try using a regex to extract the text between two tags, and then process that, and then re-insert it, but this task is probably more complicated than a single regex due to your constraints.

Here's something in Perl that works (but doesn't use regexes):

my (@a, $in_tag);
foreach(split //, $string) { # assuming $string holds our string
  $in_tag = 1 if $_ eq "<";
  $in_tag = 0 if $_ eq ">";
  if($_ eq "/" and not $in_tag) {
    push @a, " ", "/", " ";
  }
  else {
    push @a, $_;
  }
}
$string = join "", @a;

This, however, is not a regex, but a very simple parser.