Iterating over a binary file

[Sambo]

Paul Rubin wrote:

> Ville Vainio <ville.vainio at spamster_tut_remove.fi> writes:
> 
> 
>>Paul Rubin <http://phr.cx@NOSPAM.invalid> writes:
>>
>>
>>>>The above code works, but I don't like making two read() calls.  Any
>>>>way to avoid it, or a more elegant syntax?  Thanks.
>>>>
>>>You can make it even uglier:
>>>
>>>    f = file(filename, 'rb')
>>>    while 1:
>>>      data = f.read(1024)
>>>      if len(data) <= 0:
>>>        break
>>>      someobj.update(data)
>>>    f.close()
>>>
>>>There's been proposals around to add an assignment-expression operator
>>>like in C, so you could say something like
>>>
>>>    f = file(filename, 'rb')
>>>    while len(data := f.read(1024)) > 0:
>>>      someobj.update(data)
>>>    f.close()
>>>
>>It's funny, but I find the first version much more readable than the
>>second one. Especially if I consciously forget the "do lots of stuff
>>in condition part of while" indoctrination from C. If there is lots of
>>stuff in while you have to stare at it a bit more, and it becomes
>>"idiomatic", something you learn, perhaps even cookbook stuff, instead
>>of obvious-as-such.
>>
> 
> Idioms exist because they're useful, and there's already plenty of
> them in Python, like ''.join(stringlist) or "for i in xrange(n)" etc.
> 
> Maybe the condition in the while statement makes that statement twice
> as hard to read.  However, the example as a whole can still be easier,
> simply because it's shorter.
> 
> Version 1:
> 
>     Statement                              Reading difficulty
>     =========                              ==================
> 
>       f = file(filename, 'rb')                     1
>       while 1:                                     1
>         data = f.read(1024)                        1
>         if len(data) <= 0:                         1
>           break                                    1
>         someobj.update(data)                       1
>       f.close()                                    1
> 
>     Total reading difficulty:                      7
> 
> Now the second version:
> 
>     Statement                              Reading difficulty
>     =========                              ==================
> 
>        f = file(filename, 'rb')                    1
>        while len(data := f.read(1024)) > 0:        2
>          someobj.update(data)                      1
>        f.close()                                   1
> 
> 
>     Total reading difficulty:                      5
> 
> I got through college on a version of this reasoning.  I was a math
> major.  I had friends studying history and literature who said "that's
> a hard subject", but I thought they were crazy.  But in a normal math
> class, there's one textbook that you use for the whole semester, and
> you cover maybe half the chapters in it.  I was able to keep up.  But
> in a literature course, you usually have to read a different entire
> book from cover to cover EVERY WEEK.  I took a couple classes like
> that and barely survived.  Yes, it takes a lot more effort to read a
> page of a math book than a page of a novel.  When you compare the
> total reading load though, math was a much easier major than
> literature or history.  
> 
> It's the same with programs.  I'd rather read 5 lines of tight code
> that each actually does something, than 3 pages of loose code (the
> kind that's usually written in Java) that spastically meanders trying
> to do the same thing, even if the individual loose lines are easier to
> read than the tight lines.
> 

I would say, that depends on the persons competency in a given language.
Naturally once you are writing long/large programs it is better to have tight 
code, but for a newby it is too much to translate at once.
While I consider myself expert in "C" , I am still learning "C++".

That does not mean a language has to lack the capability.


Then again how large a program can you or would you want to write with python?

Cheers, Sam.