sys.stdout.write in python3 adds 11 at end of string

Question

Can someone explain why sys.stdout.write() appends 11 to my string?

$ python3
Python 3.4.3+ (default, Jul 28 2015, 13:17:50) 
[GCC         


        

Answer 1

It's NOT appended to the written string. 11 here is the return value of sys.stdout.write(), which is the number of characters written.

See write:

Write the string s to the stream and return the number of characters written.

---

It's similar to:

>>> def foo():
...     print('something', end='')
...     return 42
...
>>> foo()
something42