Python

Why a Set?

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Join Date: Jul 2005

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Reputation: bumsfeld will become famous soon enough

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bumsfeld

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Why a Set?

Nov 20th, 2005

I am making progress learning Python. and English. I understands tuples, lists and dictionaries, but sets don't make muchly sense. Why use a set? What is a set good for?

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Join Date: Sep 2005

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mawe

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Re: Why a Set?

Nov 20th, 2005

Hi!

Did you have a look at the python-docs?
This should make clear that sets are really useful

Regards, mawe

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Join Date: Jul 2005

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bumsfeld

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Re: Why a Set?

Nov 20th, 2005

Thank you mawe,

so when I take the list with duplicates and make it one set then the duplicates are gone. How can I find out which were those duplicates?

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Join Date: Jan 2006

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monkeyy

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Re: Why a Set?

Jan 9th, 2006

•

Originally Posted by bumsfeld

Thank you mawe,

so when I take the list with duplicates and make it one set then the duplicates are gone. How can I find out which were those duplicates?

you can use the list method somelist.count(x),
which returns the number of i's for which somelist[i] == x :

 Help with Code Tags 
 Python Syntax (Toggle Plain Text) 
l=list('a list of characterstrings')
for item in set(l):
	print item,'counted',l.count(item),'times'
l=list('a list of characterstrings')
for item in set(l):
	print item,'counted',l.count(item),'times'

gives

 Help with Code Tags 
 Python Syntax (Toggle Plain Text) 
a counted 3 times
  counted 3 times
c counted 2 times
e counted 1 times
...
a counted 3 times
  counted 3 times
c counted 2 times
e counted 1 times
...