new to python, help please !!

[Steven D'Aprano]

On Thursday 12 November 2015 04:48, Quivis wrote:

> On Wed, 11 Nov 2015 08:34:30 -0800, Anas Belemlih wrote:
> 
>> md5
> 
> If those are md5 values stored inside files, wouldn't it be easier to
> just hash them?
> 
> import hashlib
> 
> m1 = hashlib.sha224(open('f1').read()).hexdigest()
> m2 = hashlib.sha224(open('f2').read()).hexdigest()

I presume that the purpose of the exercise is to learn basic Python skills 
like looping.

Also, using sha224 when all you want is a simple "different"/"equal" is 
horribly inefficient. Sha224 needs to read the entire file, every single 
byte, *and* perform a bunch of expensive cryptographic operations. Consider 
reading two five GB files, the first starting with byte \x30 and the second 
starting with byte \x60. The two bytes are different, so we know the files 
differ, but sha224 still needs to do a massive amount of work.



-- 
Steve