Python3 Exec, Why Returns None?

When the code below this text, and returns the result None why? with open('exx.py', 'rb') as file: ff = compile(file.read(), 'exx.py', 'exec') snip_run = exec(ff, locals()) if 'res

Solution 1:

The problem of course is not only that print returns None, it is that exec returns None, always.

>>> exec('42') isNoneTrue

If you'd need the return value, you'd use eval:

>>>eval('42')
42

after which you'd notice that print still returns None...

Solution 2:

Thank you all decided as follows:

import sys
from io import StringIO
from contextlib import contextmanager


@contextmanagerdefstdoutIO(stdout=None):
    old = sys.stdout
    if stdout isNone:
        stdout = StringIO()
    sys.stdout = stdout
    yield stdout
    sys.stdout = old


with stdoutIO() as s:
    withopen('exx.py', 'rb') as file:
        ff = compile(file.read(), 'exx.py', 'exec')
        exec(ff, locals())
        if'result'inlocals():
            sys.stdout.write(locals().get('result'))

print(s.getvalue())

Solution 3:

Print always returns none.

Also this is not how you should ever execute code from another module. That's what import is for.