How to pick out bytes from the string of bytes?

Question

I have a payload from a pcap that looks like:

b'01005e1cd039f4cc55a050000800450000b403ef4000fa1111fd3ff7707fe99cd03907054e5900a01f353d0b00026f2e000100000172a5c12c8043'

How can I pick out bytes from a byte offset? For example, if I want the 4th to 7th bytes?

Answer 1

Just use python standard slicing:

To get the 4th to 7th byte, simply do

bytes_str = b'01005e1cd039f4cc55a050000800450000b403ef4000fa1111fd3ff7707fe99cd03907054e5900a01f353d0b00026f2e000100000172a5c12c8043'
print(bytes_str[4:7+1]) # (we add one because the stop value is exclusive)

and the output

b'5e1c'