I am absolutly new in Python and I have the following question.
From what I read on the documentation declaring a byte array I am not allowed to assign a value that doesn't come from the range 0 to 255.
Infact doing something like this:
data = bytearray(1000)
for i in range(len(data)):
data[i] = 10 - i
for b in data:
print(hex(b))
I am obtaining the following exception:
Traceback (most recent call last):
File "main.py", line 4, in <module>
data[i] = 10 - i
ValueError: byte must be in range(0, 256)
So first question: what exactly does it mean? It means that I can declare an array of bytes containing at most 256 bytes? Or am I missing something? If this reasoning is correct: in the case that I have to read a binary file containing more than 256 bytes how can I handle this situation?
Furthermore in another example I found this code snippet used to copy data from a source binary file to a destination one:
from os import strerror
srcname = input("Source file name?: ")
try:
src = open(srcname, 'rb')
except IOError as e:
print("Cannot open source file: ", strerror(e.errno))
exit(e.errno)
dstname = input("Destination file name?: ")
try:
dst = open(dstname, 'wb')
except Exception as e:
print("Cannot create destination file: ", strerr(e.errno))
src.close()
exit(e.errno)
buffer = bytearray(65536)
total = 0
try:
readin = src.readinto(buffer)
while readin > 0:
written = dst.write(buffer[:readin])
total += written
readin = src.readinto(buffer)
except IOError as e:
print("Cannot create destination file: ", strerr(e.errno))
exit(e.errno)
print(total,'byte(s) succesfully written')
src.close()
dst.close()
As you can see it is declaring a bytearray containing more than 255 element:
buffer = bytearray(65536)
I think that I am missing something. How exactly does it work?
