python source fileencoding

Thu, May 22, 2014

Some of the python source file starts with -*- coding: utf-8 -*-. This particular linetells python interpreter all the content (byte string) is utf-8 encoded. Lets see how it affects the code.

uni1.py:

# -*- coding: utf-8 -*-
print("welcome")
print("animé")

output:

➜  code$ python2 uni1.py
   welcome
   animé

Third line had a accented character and it wasn’t explictly stated as unicode. print function passed successfully.Since first line instructed interpreter all the sequences from here on will follow utf-8, so it worked.

What if first line was missing ?

uni2.py

print("welcome")
print("animé")

output:

code$  python2 uni2.py
File "uni2.py", line 2
SyntaxError: Non-ASCII character '\xc3' in file uni2.py on line 2, but no encoding declared; see http://www.python.org/peps/pep-0263.html for details

Now python complains that Non-ASCII character is found since default encoding is ASCII.More about source encoding can be found in PEP 263

Always set encoding in first or second line of python file.