Make ipython notebook print in real time

Question

Ipython Notebook doesn't seem to print results in real time, but seems to buffer in a certain way and then bulk output the prints. How can I make ipython print my results as soon as the print command is processed?

Example code:

import time   def printer():     for i in range(100):         time.sleep(5)         print i 

Supposing that the above code is in a file that is imported. How could I make it that when I call the printer function it prints a number every 5 seconds and not all the numbers at the very end?

Please note that I cannot edit the function printer() because I get it from some external module. I want the to change the configs of ipython notebook somehow so that it doesn't use a buffer. Therefore, I also do not wish to use sys.stdout.flush(), I want to do it in real-time according to the question, I don't want any buffer to start with.

I also tried loading ipython notebook with the command:

ipython notebook --cache-size=0 

but that also doesn't seem to work.

Answer 1

This is merely one of the answers to the question suggested by Carsten incorporating the __getattr__ delegation suggested by diedthreetimes in a comment:

import sys oldsysstdout = sys.stdout class flushfile():     def __init__(self, f):         self.f = f     def __getattr__(self,name):          return object.__getattribute__(self.f, name)     def write(self, x):         self.f.write(x)         self.f.flush()     def flush(self):         self.f.flush() sys.stdout = flushfile(sys.stdout) 

In the original answer, the __getattr__ method is not implemented. Without that, it fails. Other variants in answers to that question also fail in a notebook.

In a notebook, sys.stdout is an instance of IPython.kernel.zmq.iostream.OutStream and has a number of methods and attributes not present in the usual sys.stdout. Delegating __getattr__ allows a flushfile to masquerade as a ...zmq.iostream.OutStream duck.

This works in a python 2.7 notebook run with ipython 3.1.0