How do I ensure I always get a list of matches from Python's Regular Expressions?

Question

I'm trying to pull some information (no recursion necessary) from a jsp page (malformed xml) similar to this:

<td>
<html:button ...></html:button>
<html:submit ...></html:submit></td>

And a regex:

<html:(button|submit|cancel)[\s\S]*?</html:(button|submit|cancel)>

re.findall() is giving me a list of tuples, like so:

[('button','button'),('button','button')]

Which I understand from the documentation is correct, but I'm looking to get something more like:

["<html:button ...>","<html:button ...>"]

What is the appropriate way to get the outcome I expect?

Answer 1

Aside from the fact that a regex probably isn't what you want to do this with, you want to put the bit you want in groups using parentheses. If you want everything up to the closing </html:whatever> tag, then you want something like this:

(<html:(button|submit|cancel)[\s\S]*?)</html:(button|submit|cancel)>

If you just want the <html:button> bit, use:

(<html:(button|submit|cancel)>)[\s\S]*?</html:(button|submit|cancel)>

e.g.

from

<html:button>foobar</html:submit>

you get:

('<html:button>', 'button', 'submit')

If you want to get the foobar from above, use:

(<html:(button|submit|cancel)>)([\s\S]*?)</html:(button|submit|cancel)>

to get:

('<html:button>', 'button', 'foobar', 'submit')

Note that it is not, in general, possible to match opening and closing tags (note that <html:button> is opened, and </html:submit> closes in the example above). If you need to do that, use a proper parser.

Answer 2

Your (button|submit|cancel) getting capture, so add ?: in brackets like (?:

>>> re.findall('<html:(?:button|submit|cancel)[\s\S]*?</html:(?:button|submit|cancel)>',TheHTMLWhichShouldntParseWithRegex)
['<html:button ...></html:button>', '<html:submit ...></html:submit>']