regular expressions help

[David]

On Thu, 19 Sep 2019 at 19:34, Pradeep Patra <smilesonisamal at gmail.com> wrote:

> Thanks David for your quick help. Appreciate it. When I tried on python 2.7.3 the same thing you did below I got the error after matches.group(0) as follows:
>
> AttributeError: NoneType object has no attribute 'group'.
>
> I tried to check 'None' for no match for re.search as the documentation says but it's not working.
>
> Unfortunately I cannot update the python version now to 2.7.13 as other programs are using this version and need to test all and it requires more testing. Any idea how I can fix this ? I am ok to use any other re method(not only tied to re.search) as long as it works.

Hi again Pradeep,

We are now on email number seven, so I am
going to try to give you some good advice ...

When you ask on a forum like this for help, it is very
important to show people exactly what you did.
Everything that you did. In the shortest possible
way that demonstrates whatever issue you are
facing.

It is best to give us a recipe that we can follow
exactly that shows every step that you do when
you have the problem that you need help with.

And the best way to do that is for you to learn
how to cut and paste between where you run
your problem code, and where you send your
email message to us.

Please observe the way that I communicated with
you last time. I sent you an exact cut and paste
from my terminal, to help you by allowing you to
duplicate exactly every step that I made.

You should communicate with us in the same
way. Because when you write something like
your most recent message

> I got the error after matches.group(0) as follows:
> AttributeError: NoneType object has no attribute 'group'.

this tells us nothing useful!! Because we cannot
see everything you did leading up to that, so we
cannot reproduce your problem.

For us to help you, you need to show all the steps,
the same way I did.

Now, to help you, I found the same old version of
Python 2 that you have, to prove to you that it works
on your version.

So you talking about updating Python is not going
to help. Instead, you need to work out what you
are doing that is causing your problem.

Again, I cut and paste my whole session to show
you, see below. Notice that the top lines show that
it is the same version that you have.

If you cut and paste my commands into
your Python then it should work the same way
for you too.

If it does not work for you, then SHOW US THE
WHOLE SESSION, EVERY STEP, so that we can
reproduce your problem. Run your python in a terminal,
and copy and paste the output you get into your message.

$ python
Python 2.7.3 (default, Jun 20 2016, 16:18:47)
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import re
>>> mystr = "where is my-dog"
>>> pattern = re.compile(r'my-dog$')
>>> matches = re.search(pattern, mystr)
>>> matches.group(0)
'my-dog'
>>>

I hope you realise that the re module has been used
by thousands of programmers, for many years.
So it's extremely unlikely that it "doesn't work" in a way that
gets discovered by someone who hardly knows how to use it.