Alternative to execfile in Python 3?

Question

Python 2 had the builtin function execfile, which was removed in Python 3.0. This question discusses alternatives for Python 3.0, but some considerable changes have been made since Python 3.0.

What is the best alternative to execfile for Python 3.2, and future Python 3.x versions?

Answer 1

The 2to3 script replaces

execfile(filename, globals, locals)

by

exec(compile(open(filename, "rb").read(), filename, 'exec'), globals, locals)

This seems to be the official recommendation. You may want to use a with block to ensure that the file is promptly closed again:

with open(filename, "rb") as source_file:
    code = compile(source_file.read(), filename, "exec")
exec(code, globals, locals)

You can omit the globals and locals arguments to execute the file in the current scope, or use exec(code, {}) to use a new temporary dictionary as both the globals and locals dictionary, effectively executing the file in a new temporary scope.