Regex: Remove empty-element tags for xml

Question

I'd like to replace all self-closed elements to the long syntax (because my web-browser is tripping on them).

Example

<iframe src="http://example.com/thing"/>

becomes

<iframe src="http://example.com/thing"></iframe>

I'm using python's flavor of regex.

Thom Smith · Accepted Answer · 2009-10-16 05:55:53Z

4

None of those solutions will accommodate attributes like foo="/>". Try:

s:<([\w\-_]+)((?:[^'">]|'[^']*'|"[^"]*")*)/\s*>:<$1$2></$1>:

Exploded to show detail:

<
    ([\w\-_]+)    # tag name
    (
        [^'">]*| # "normal" characters, or
        '[^']*'| # single-quoted string, or
        "[^"]*"  # double-quotes string
    )*
    /\s*         # self-closing
>

This should always work provided that the markup is valid. (You could rearrange this using lazy quantifiers if you so chose; e.g. '[^']' => '.*?'.)

edited Oct 16, 2009 at 5:55

answered Oct 16, 2009 at 5:42

Thom Smith

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2 Comments

nickf Over a year ago

<div class="/>"> isn't valid HTML is it?

Thom Smith Over a year ago

You're looking at attribute names in HTML 5. '/' is permitted between quotes, and '>', while prohibited, is (sadly) commonly seen in production code. Conservative in what you emit, liberal in what you accept.

Michael La Voie · Accepted Answer · 2009-10-16 17:50:50Z

2

Use this python regex:

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

It differs from @Kinopiko's in that it will handle nested elements.

Explanation of Regex

Find the opening bracket: <
Find the word following: (\w+)
Find any and all tags between the tag name and its closing bracket except for another open bracket to handle nested tags: [^<]*?
Find the closing tag: >

Then just replace with this statement:

\1></\2>

edited Oct 16, 2009 at 17:50

answered Oct 16, 2009 at 5:29

Michael La Voie

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2 Comments

Paul Tarjan Over a year ago

shouldn't the second < be a > ?

user181548 Over a year ago

If you just want to make sure it doesn't swallow another tag then either one is ok.

2 revs user181548 · Accepted Answer · 2009-10-16 05:31:47Z

0

In Perl,

s:(<(\w+)[^>]*?)/>:$1></$2>:

will do it.

edited Oct 16, 2009 at 5:31

community wiki

2 revs
user181548

1 Comment

Michael La Voie Over a year ago

I tested it and it trips up on <div><iframe src="example.com/thing"/></div> for me. Does it properly handle that case for you?

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