How to show source code for dynamically created ("custom") function in IPython?

Question

In an IPython session, I usually define custom functions...problem is, sometimes I want to see the actual code for these functions. So far, I have not been able to find a way to display this. Using ? and ?? simply returns "Dynamically generated function. No source code available." Is there any way to display source code for user-defined functions?

Answer 1

If you are looking for the source for an interactively-defined function, you can find the most recent definition of it in iPython's history:

[i for (i, l) in  enumerate(_ih) if l.startswith('def foo(')][-1]

Then you can edit that line:

%edit 42

It'll open up Notepad or another text editor with the function definition in it.

Or you can save to a file:

%save foo.py 42

Answer 2

I am using python 2.7.4 and iPython 0.13.2.

I can see the source of a dynamically created function in iPython using ?? before the function name:

In [8]: ??sort_words
Type:       function
String Form:<function sort_words at 0x189b938>
File:       /tmp/ipython_edit_yc1TIo.py
Definition: sort_words(s)
Source:
def sort_words(s):
    x = re.findall(r'\W+(\w+)', s)
    x.sort()
    for i in x:
        print i

Maybe this is now available in newer versions of iPython? What version are you using?