pythontypesbyte

In python, why do some byte strings have \x in them, and others dont?

Im struggling to understand why and how some python byte strings have \x in them, and others dont.

For example, I have this assertion:

AssertionError: 
actual b'00000001'
expected b'\x00\x00\x00\x01'

Why are they not equal? They are both byte strings, 4 bytes long with a value 1. How do I make them look the same, and how do I make them "be" the same? It seems one has come from a string string, and the other made from integer - but why dont they come out the same when converted to bytes?

Hopefully I've not missed something else.

Thanks

Solution

  • They are not the same thing. The \x denotes a hexadecimal value.

    Without the \x it is just a raw byte string with each character representing its own integer value.

    To demonstrate:

    >>> a = b'00000001'
>>> b = b'\x00\x00\x00\x01'
>>> int.from_bytes(a, 'little')
3544385890265608240
>>> int.from_bytes(b, 'little')
16777216
>>> len(a)
8
>>> len(b)
4
>>> a.hex()
'3030303030303031'
>>> b.hex()
'00000001'
>>> a[0]
48
>>> b[0]
0

    Also, since we can see from above that b'0' is represented by 48 and since 48 = 16*3 that means b'\x30' should be equal to b'0'

    >>> b'0' == b'\x30'
True