The Cost of Dynamism (was Re: Pyhon 2.x or 3.x, which is faster?)

[Mark Lawrence]

On 21/03/2016 19:43, BartC wrote:
> On 21/03/2016 02:02, Mark Lawrence wrote:
>> On 21/03/2016 01:35, Chris Angelico wrote:
>>> On Mon, Mar 21, 2016 at 12:28 PM, Mark Lawrence
>>> <breamoreboy at yahoo.co.uk> wrote:
>>>> I got to line 22, saw the bare except, and promptly gave up.
>>>
>>> Oh, keep going, Mark. It gets better.
>>>
>>> def readstrfile(file):
>>>      try:
>>>          data=open(file,"r").read()
>>>      except:
>>>          return 0
>>>      return data
>>>
>>> def start():
>>>      psource=readstrfile(infile)
>>>      if psource==0:
>>>          print ("Can't open file",infile)
>>>          exit(0)
>>>
>>> So, if any exception happens during the reading of the file, it gets
>>> squashed, and 0 is returned - which results in a generic message being
>>> printed, and the program terminating, with return value 0. Awesome!
>>>
>>> ChrisA
>>>
>>
>> The essential question is "which is faster?".  Who cares about trivial
>> little details like the user being given false data, as (say) they can
>> open the file but can't read it.  Or inadvertantly writing an infinite
>> loop and not being able to CTRL-C out of it, having to revert to your OS
>> to kill the rogue that's killing your CPU.
>>
>> 25 years of trying to teach people how to write Pythonic code and this
>> is how far we've got.  Heck, I think I'll see my GP later today for some
>> more, more powerful, tranquilisers.
>>
>
> This code was adapted from a program that used:
>
>     readstrfile(filename)
>
> which either returned the contents of the file as a string, or 0.

So you've used a dreadful piece of code, not recognising it as such. 
This again indicates that you know precisely nothing about Python, apart 
from the well known fact that relative to some languages, it is rather 
slow at run time.  In programmer time it more than makes up for that. 
Horses for courses?

>
> That's all. My Python version was thrown together as I don't know if
> there's a similar function to do the same.

"As I don't know", out of the horse's mouth.

>
> If you want to talk about Pythonic, I don't see why that file API
> doesn't count (the original is buried in a library).

Precisely, what does the file API have to do with a dreadfully written 
piece of code misusing exceptions?

>
> Or does Pythonic mean bristling with exceptions and classes and what-not?
>

I've all ready pointed out that Python prefers EAFP to LBYL via 
exceptions.  Classes not necessarily, especially in the days of the 
namedtuple.

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence