[Tutor] Re: print as columns

[Christopher Smith]

arcege@speakeasy.net writes:
> Compare the lengths, not the content.

Thanks for persisting in pointing out the error.  I had a bad
test case.  I now see that len(max.. is wrong:

>>> a=[1]*3
>>> b=[7]
>>> len(max(a,b))
1

Whereas what you said is right:
>>> max(map(len,(a,b)))
3

Which works on the pathological case as long as you add a 
dummy list--or just a comma in the tuple of lists (b,) 
instead of (b):
>>> max(map(len,(b,)))
1

If you forget the comma, you may get this:
>>> max(map(len,(b)))
Traceback (most recent call last):
  File "<input>", line 1, in ?
TypeError: len() of unsized object

Finally, max applies itself iteratively so reduce isn't necessary 
but it works, too.
>>> reduce(max,map(len,(b,)))
1

I wrote:
> So in a function you could have:
> 
> def pcolumns(...,*lists):
> 	n=len(max(lists,[]))
> 
Uh-humm, I should have said: 
	n=max(map(len,(lists,)))

Thanks again!

/c