Am 30.05.2013 21:22, schrieb Ned Batchelder:
On 5/30/2013 2:26 PM, Mok-Kong Shen wrote:
Am 27.05.2013 17:30, schrieb Ned Batchelder:
On 5/27/2013 10:45 AM, Mok-Kong Shen wrote:
From an int one can use to_bytes to get its individual bytes,
but how can one reconstruct the int from the sequence of bytes?
The next thing in the docs after int.to_bytes is int.from_bytes:
http://docs.python.org/3.3/library/stdtypes.html#int.from_bytes
I am sorry to have overlooked that. But one thing I yet wonder is why
there is no direct possibilty of converting a byte to an int in [0,255],
i.e. with a constrct int(b), where b is a byte.
Presumably you want this to work:
>>> int(b'\x03')
3
But you also want this to work:
>>> int(b'7')
7
These two interpretations are incompatible. If b'\x03' becomes 3, then
shouldn't b'\x37' become 55? But b'\x37' is b'7', and you want that to
be 7.
b'7' is the byte with the character 7 in a certain code, so that's
ok. In other PLs one assigns an int to a byte, with that int in either
decimal notation or hexadecimal notation, or else one assigns a
character to it, in which case it gets the value of the character
in a certain code. What I don't yet understand is why Python is
apprently different from other PLs in that point in not allowing direct
coersion of a byte to an int.
M. K. Shen
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