Uniquifying a list?

[Tim Chase]

Is there an obvious/pythonic way to remove duplicates from a
list (resulting order doesn't matter, or can be sorted
postfacto)? My first-pass hack was something of the form

>>> myList = [3,1,4,1,5,9,2,6,5,3,5]
>>> uniq = dict([k,None for k in myList).keys()

or alternatively

However, it seems like there's a fair bit of overhead
here...creating a dictionary just to extract its keys, or
creating a set, just to convert it back to a list. It feels
like there's something obvious I'm missing here, but I can't
put my finger on it.

Thanks...

-tkc

 

[Edward Elliott]

You could do

>>> uniq = [x for x in set(myList)]

but that's not really any different than what you already have.

This almost works:

>>> uniq = [x for x in myList if x not in uniq]

except the r-val uniq isn't updated after each iteration.

Personally I think list(set(myList)) is as optimal as you'll get.

Is there an obvious/pythonic way to remove duplicates from a list
(resulting order doesn't matter, or can be sorted postfacto)? My
first-pass hack was something of the form

myList = [3,1,4,1,5,9,2,6,5,3,5]
uniq = dict([k,None for k in myList).keys()

or alternatively

However, it seems like there's a fair bit of overhead here...creating a
dictionary just to extract its keys, or creating a set, just to convert
it back to a list. It feels like there's something obvious I'm missing
here, but I can't put my finger on it.

Thanks...

-tkc

 

[John Machin]

Is there an obvious/pythonic way to remove duplicates from a list
(resulting order doesn't matter, or can be sorted postfacto)?

Google is your friend:
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52560

 

[Rene Pijlman]

Tim Chase:

Is there an obvious/pythonic way to remove duplicates from a
list (resulting order doesn't matter,

Use a set.
http://www.python.org/doc/lib/types-set.html

 

[bearophileHUGS]

There is my version too:
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/438599

Bye,
bearophile