Please tell me how to execute python file in Ubuntu by double clicking on file. (Posting On Python-List Prohibited)

[Python]

On Wed, Dec 06, 2017 at 10:35:58AM +1100, Steve D'Aprano wrote:
> On Tue, 5 Dec 2017 07:58 pm, Lawrence D’Oliveiro wrote:
> 
> > On Tuesday, December 5, 2017 at 3:39:26 AM UTC+13, Rick Johnson wrote:
> >> 
> >> Sounds like your OS file associations are all botched-up ...
> > 
> > Linux doesn’t do “OS file associations”.
> 
> 
> Then how does my Linux box know that when I double-click on a text file, it
> launches kwrite rather than (say) the Gimp or LibreOffice?

The answer to that is (sadly) complicated.  How it knows indeed
depends on the context of the click, what desktop environment you're
using, what application(s) you're using, and what configurations
you've made to those things to address any file associations.  There
isn't one answer.  On the same system, the answer could well be
completely different for any two users, or even for the same user,
given different application contexts.  The latter is less true than it
used to be, but still true nonetheless.

Granted, this isn't a very useful answer, but it's the only one you
can give that is certainly correct, without more context.