CODEWITHSUNDEEP
pythonlistpython-2.7counter
Majesty Eksa Permana
Majesty Eksa Permana

Reputation: 81

Counter list python 2.7

I have list like this:

Pasang = [0, 4, 4, 5, 1, 7, 6, 7, 5, 7, 4, 9, 0, 10, 1, 10,...., 23, 9, 23, 7, 23]

I count item from that list:

satuan = Counter(pasang)

then I get :

Counter({5: 10, 6: 7, 0: 5, 1: 5, 7: 5, 10: 4, 11: 4, 15: 4,...,14: 1, 21: 1})

I want to get key from counter, so i do this:

satu = satuan.keys()

and I get sorted list like this:

[0, 1, 2, 4, 5,...,21, 22, 23]

but I need an output like this (not sorted):

[5, 6, 0, 1,...,14, 21]

Sorry for my bad english.

Upvotes: 5

Views: 1068

Answers (2)

ZdaR
ZdaR

Reputation: 22954

If you want to maintain the order then have a look at the Counter object you just created, it has elements sorted w.r.t to the frequency in decreasing order and you can also achieve the same behaviour by sorting the keys on frequency and setting the reverse flag to be True

import collections
Pasang = [0, 4, 4, 5, 1, 7, 6, 7, 5, 7, 4, 9, 0, 10, 1, 10, 23, 9, 23, 7, 23]

a = collections.Counter(Pasang)

keys = sorted(a.keys(), key = lambda x:a[x], reverse = True)
print a
print keys
>>> Counter({7: 4, 4: 3, 23: 3, 0: 2, 1: 2, 5: 2, 9: 2, 10: 2, 6: 1})
>>> [7, 4, 23, 0, 1, 5, 9, 10, 6]

Upvotes: 0

JuniorCompressor
JuniorCompressor

Reputation: 20015

You probably need:

[key for key, freq in c.most_common()]

where c is the Counter instance.

most_common will return pairs of keys and frequencies, in decreasing order of frequency. Then you extract the key part using a comprehension.

Upvotes: 4

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