Python如何读写字节数据

# Read the entire file as a single byte string
with open('somefile.bin', 'rb') as f:
  data = f.read()

# Write binary data to a file
with open('somefile.bin', 'wb') as f:
  f.write(b'Hello World')

> # Text string
> t = 'Hello World'
> t[0]
'H'
> for c in t:
...   print(c)
...
H
e
l
l
o
...
> # Byte string
> b = b'Hello World'
> b[0]
72
> for c in b:
...   print(c)
...
72
101
108
108
111
...
>

with open('somefile.bin', 'rb') as f:
  data = f.read(16)
  text = data.decode('utf-8')

with open('somefile.bin', 'wb') as f:
  text = 'Hello World'
  f.write(text.encode('utf-8'))

import array
nums = array.array('i', [1, 2, 3, 4])
with open('data.bin','wb') as f:
  f.write(nums)

> import array
> a = array.array('i', [0, 0, 0, 0, 0, 0, 0, 0])
> with open('data.bin', 'rb') as f:
...   f.readinto(a)
...
16
> a
array('i', [1, 2, 3, 4, 0, 0, 0, 0])
>