What is a Python code object?

Question

While trying to use Python\'s \"exec\" statement, I got the following error:

TypeError: exec: arg 1 must be a string, file, or code object

I do

Answer 1

Code objects are described here:

Code objects represent byte-compiled executable Python code, or bytecode. The difference between a code object and a function object is that the function object contains an explicit reference to the function’s globals (the module in which it was defined), while a code object contains no context; also the default argument values are stored in the function object, not in the code object (because they represent values calculated at run-time). Unlike function objects, code objects are immutable and contain no references (directly or indirectly) to mutable objects.

Answer 2

One way to create a code object is to use compile built-in function:

>>> compile('sum([1, 2, 3])', '', 'single')
<code object <module> at 0x19ad730, file "", line 1>
>>> exec compile('sum([1, 2, 3])', '', 'single')
6
>>> compile('print "Hello world"', '', 'exec')
<code object <module> at 0x19add30, file "", line 1>
>>> exec compile('print "Hello world"', '', 'exec')
Hello world

also, functions have the function attribute __code__ (also known as func_code in older versions) from which you can obtain the function's code object:

>>> def f(s): print s
... 
>>> f.__code__
<code object f at 0x19aa1b0, file "<stdin>", line 1>

Answer 3

There is an excellent blog post by Dan Crosta explaining this topic, including how to create code objects manually, and how to disassemble them again:

Exploring Python Code Objects