在python中将int转换为字节流

Question

I am new to python so please bear with if it sounds a novice question. I looked it up but different sources tell me different things so I decided to ask it here. And doc is not very clear.

I have an int that I want to convert to bytes.

#1024 should give me 0000010000000000
print bytes([1024])
[1024]

If I use bytes() I assume I get a list since when I print I end up getting [1024]. However if I do

print bytes([1024])[0] 
[

I get [ back. Why is this? So it does not return a list?

Is there a way to get the byte streams back given an integer? Ideally I want something as follows:

x = tobyte(1024)
print x[0] #should give me  0  00000000
print x[1] #should give me  8  00000100

I need to be able to use x[0] elsewhere in the code ie to be passed to base64 encode where I expect my data to be 64 bits

Answer 1

To get the individual bytes from an integer, use struct :

individual_bytes = struct.unpack("BB", struct.pack("<H", 1024))

First, "<I" packs the integer as a 16-bit value, using little-endian ordering. Then "BB" unpacks the byte string into two separate 8-bit values.