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Date: Tue, 14 Jun 2011 01:09:07 +1000
Subject: Re: What is the most efficient way to compare similar contents in two lists?
From: Chris Angelico <rosuav@gmail.com>
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:7519

On Tue, Jun 14, 2011 at 12:58 AM, Zachary Dziura <zcdziura@gmail.com> wrote=
:
> if set(source_headers) =3D=3D set(target_headers):
> =A0 =A0similar_headers =3D len(source_headers)

Since you're making sets already, I'd recommend using set operations -
same_headers is the (length of the) intersection of those two sets,
and different_headers is the XOR.

# If you need the lists afterwards, use different variable names
source_headers =3D set(source_headers)
target_headers =3D set(target_headers)
similar_headers =3D len(source_headers & target_headers)
different_headers =3D len(source_headers ^ target_headers)

Chris Angelico