Difference between struct.unpack() and int.from_bytes()?

Question

Is there a difference between the two? When should I use one over the other? They do the same thing basically except struct.unpack() works for multiple byte sequences. Should I still use struct.unpack() if I only need to convert one byte sequence, or should I use int.from_bytes()? I'm just curious to know.

Answer 1

Well, for starters, int.from_bytes will only ever return a single int object, so if you want to create anything other than an int , you can't use int.from_bytes .

Second, struct.unpack only supports fixed-length numeric C types. int.from_bytes supports arbitrarily-sized integers (which int objects are):

>>> int.from_bytes(b'\xff'*8, 'little')
18446744073709551615
>>> int.from_bytes(b'\xff'*10, 'little')
1208925819614629174706175
>>> int.from_bytes(b'\xff'*100, 'little')
6668014432879854274079851790721257797144758322315908160396257811764037237817632071521432200871554290742929910593433240445888801654119365080363356052330830046095157579514014558463078285911814024728965016135886601981690748037476461291163877375

If you only ever want a single integer, I would probably just use int.from_bytes . The general purpose of the struct module is to parse C structs into Python objects.