Question

Python regular expression I have a string that contains keywords but sometimes the keywords dont exist and they are not in any particular oder. I need help with the regular expression.

Keywords are:

Up-to-date
date added
date trained

These are the keywords i need to find amongst a number of other keywords and they may not exist and will be in any order.

What the sting looks like

<div>
<h2 class='someClass'>text</h2>

 blah blah blah Up-to-date blah date added blah

</div>

what i’ve tried:

regex = re.compile('</h2>.*(Up\-to\-date|date\sadded|date\strained)*.*</div>') 

regex = re.compile('</h2>.*(Up\-to\-date?)|(date\sadded?)|(date\strained?).*</div>')

re.findall(regex,string) 

The outcome i’m looking for would be:

If all exists
['Up-to-date','date added','date trained']

If some exists
['Up-to-date','','date trained']

Answer 1

Does it have to be a regex? If not, you could use find:

In [12]: sentence = 'hello world cat dog'

In [13]: words = ['cat', 'bear', 'dog']

In [15]: [w*(sentence.find(w)>=0) for w in words]
Out[15]: ['cat', '', 'dog']