hacking and gonzo since 2000

Python's set datatype

Here's a little tip for the friday. Python's set datatype was added in Python2.4 and it's really great and can be used in different situations.

First, when you want to filter out a list to extract only unique items:

print set([1, 1, 3, 4, 5, 3, 2])

Second, when you want to find out how two lists relate, for example, find out all the elements they have in common:

print set([1, 1, 3, 4, 5, 3, 2]).difference([1, 2])
print set([1, 1, 3, 4, 5, 3, 2]).intersection([1, 2])

That's it :)

Code · Python · Tips • 6. Feb 2009