Divide byte string and return as a byte string

Question

Write a function called div2bstr that takes a byte string (bstr) and returns a byte string. Each character in the byte string is divided by 2 (integer division) and assembled into a new byte string. Return the new byte string using a string and for loop.

I have tried to implement this with an empty string then concatenating it with a for loop but I am unable to get the correct answer.

def div2bstr(bstr):
    final_str = ''
    final_str += [i//2 for i in bstr]
    return final_str

When calling div2bstr(b'Hello'), the expected result is b'$2667'.

I receive errors when I run mine:

final_str += [i//2 for i in bstr]

TypeError: can't concat bytes to list

I understand that when I am i is an integer and that’s why it is unable to concatenate, but I don’t know how to fix this issue and get the proper result.

Though DYZ has given a great answer already, I believe there are something you need to pay attention in your code: 1) final_str='' it is a str instead of byte string 2) final_str += [i//2 for i in bstr] left side is a str while right side is an int list, which is obviously incorrect 3) I believe you have something else happening in code as the TypeError seems not reflecting your mistakes. — Adrian Shum
– Adrian Shum, Commented May 8, 2019 at 6:33
4) There is no for-loop. [i//2 for i in bstr] is what we call list comprehension, it is not a for loop (although you can write a equivalent for-loop based on that) — Adrian Shum
– Adrian Shum, Commented May 8, 2019 at 6:37

DYZ · Accepted Answer · 2019-05-08 04:50:05Z

3

Convert the list of bytes into a bytes object, and you can write the whole function body in one line.

def div2bstr(bstr):
    return bytes(i//2 for i in bstr)

answered May 8, 2019 at 4:50

DYZ

57.3k10 gold badges73 silver badges101 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Divide byte string and return as a byte string

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related