Question on lists

[Martin Maney]

Aahz <aahz at pythoncraft.com> wrote:
> Elaine Jackson <elainejackson7355 at home.com> wrote:
>>
>>If x is the given sequence, then
>>[x[i] for i in filter(lambda i: i==0 or x[i-1]<>x[i], range(len(x)))]
>>is what you want.

> Please report to the UnPythonic Activities Committee.  ;-)

Has the committee considered the other functional solution?

>>> def dedupe(lst, x):   
...     if not lst or lst[-1] != x:
...             lst.append(x)
...     return lst
... 
>>> reduce(dedupe, l, [])
['a', 'b', 'c', 'd', 'e']

If it would help, I'm sure we could get an obfuscation expert to make
it into one line, but without a first-class conditional expression,
it's nothing but a circus trick.  Perl envy, like.

Oh, okay, twist my arm...

>>> reduce(lambda r,x: (not r or r[-1]!=x) and r.append(x) or r, l, [])
['a', 'b', 'c', 'd', 'e']

I knew reduce would come in handy for something.

> "To me vi is Zen.  To use vi is to practice zen.  Every command is a
> koan.  Profound to the user, unintelligible to the uninitiated.  You
> discover truth everytime you use it."  --reddy at lion.austin.ibm.com

Apparently vi also shares with koans the characteristic of battering
down the walls of rationality.  :-)

-- 
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of the loser is perfectly clear.  It is the nation's confidence
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 - Justice John Paul Stevens, from his dissenting opinion Dec 12, 2000