Filtering out non-readable characters

[Peter Hansen]

Bengt Richter wrote:
>  >>> identity = ''.join([chr(i) for i in xrange(256)])
>  >>> unprintable = ''.join([c for c in identity if c not in string.printable])

And note that with Python 2.4, in each case the above square brackets 
are unnecessary (though harmless), because of the arrival of "generator 
expressions" in the language.  (Bengt knows this already, of course, but 
his brain is probably resisting the reprogramming.  :-) )

-Peter