Python 3.x and bytes

Ethan Furman ethan at stoneleaf.us
Tue May 17 16:20:45 EDT 2011


Felipe Bastos Nunes wrote:
> 2011/5/17 Ethan Furman wrote:
>> 
>> In Python 3 one can say
>> 
>> --> huh = bytes(5)
>> 
>> Since the bytes type is actually a list of integers, I would have
>>     expected this to have huh being a bytestring with one element -- the
>> integer 5.  Actually, what you get is:
>> 
>> --> huh
>> b'\x00\x00\x00\x00\x00'
>> 
>> or five null bytes.  Note that this is an immutable type, so you
>> cannot go in later and say
>> 
>> --> huh[3] = 9
>> Traceback (most recent call last):
>>  File "<stdin>", line 1, in <module>
>> TypeError: 'bytes' object does not support item assignment
>> 
>> 
>> So, out of curiosity, does anyone actually use this, um, feature?
 >
> They accept .replace(b"00", b"12") for example.

So they do.  Although that particular example doesn't work since b'0' is 
the integer 48...

--> huh.replace(b'00',b'12')
b'\x00\x00\x00\x00\x00'


The big question, though, is would you do it this way:

some_var = bytes(23).replace(b'\x00', b'a')

or this way?

some_var = bytes(b'a' * 23)

~Ethan~



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