Best way to convert sequence of bytes to long integer

Alf P. Steinbach alfps at
Wed Jan 20 19:27:34 CET 2010

* Mark Dickinson:
> On Jan 20, 7:36 am, Steven D'Aprano <st... at REMOVE-THIS-
>> wrote:
>> I have a byte string (Python 2.x string), e.g.:
>> s = "g%$f yg\n1\05"
>> assert len(s) == 10
>> I wish to convert it to a long integer, treating it as base-256.
> By the way, are you willing to divulge what you're using this
> functionality for?  When trying to hack out the API for int.to_bytes
> and int.from_bytes on the mailing list and bug tracker, some of the
> discussion about use-cases seemed a little too much like guesswork;
> I'd be curious to find out about real-life use-cases.

One possibility is that Steven wants to apply bitlevel and/or arithmetic 
operations for e.g. some custom cryptographic thing. The string that he uses as 
example is not completely unlike a message digest.

Another possibility is custom serialization/deserialization.

But it would be nice to know what it's actually about...


- Alf

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