Print a dict sorted by values

Question

I'm basically trying to iterate through a dict and print out the key / values from largest value to lowest. I have been searching this site and a lot of people are using lambda but I'm not really sure how its working so I'm trying to avoid it for now.

dictIterator = iter(sorted(bigramDict.iteritems()))
for ngram, value in dictIterator:
    print("There are " + str(value) + " " + ngram)

Looking over the code above I assumed it would make an iterator which returns the key/value pairs in order from largest to smallest but it's not.

Can anyone see what the problem is? or another method of doing this?

look at this: http://stackoverflow.com/questions/613183/python-sort-a-dictionary-by-value — Alex Emelin, Jun 27 '12 at 14:58

oDDsKooL · Accepted Answer · 2013-05-31T13:14:57.000

34

One can take advantage of the fact that sort works on tuples by considering the first element as more important than the second etc:

d = { "a":4, "c":3, "b":12 }
d_view = [ (v,k) for k,v in d.iteritems() ]
d_view.sort(reverse=True) # natively sort tuples by first element
for v,k in d_view:
    print "%s: %d" % (k,v)

Output:

b: 12
a: 4
c: 3

EDIT: one-liner, generator expression:

sorted( ((v,k) for k,v in d.iteritems()), reverse=True)

Output:

[(12, 'b'), (4, 'a'), (3, 'c')]

edited May 31 '13 at 13:14

answered Jun 27 '12 at 14:56

oDDsKooL

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thanks! Python 3 one-liner: `sorted( ((v,k) for k,v in d.items()), reverse=True) ` – tegan Sep 11 '18 at 01:40

Emmanuel · Answer 2 · 2019-12-23T13:45:43.917

25

You can use the key parameter of sorted to sort by the 2nd item:

>>> d = { "a":4, "c":3, "b":12 }
>>> from operator import itemgetter
>>> for k, v in sorted(d.items(), key=itemgetter(1)):
    print k, v


c 3
a 4
b 12
>>>

EDIT: one-liner, in opposite order:

>>> d = {"a": 4, "c": 3, "b": 12}
>>> [(k, v) for k, v in sorted(d.items(), key=lambda x: x[1], reverse=True)]
[('b', 12), ('a', 4), ('c', 3)]
>>>

edited Dec 23 '19 at 13:45

answered Jun 27 '12 at 14:59

Emmanuel

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72

These sorts the opposite way. Mind editing to reverse the order (so that it goes from largest to smallest)? Thanks! – Ward W Dec 19 '19 at 03:07

score 4 · Answer 3 · answered Jun 27 '12 at 14:58

4

>>> d = { "a":4, "c":3, "b":12 }
>>> from operator import itemgetter
>>> lst = sorted(d.iteritems(), key=itemgetter(1))
>>> for t in lst: print '%s : %d' % (t[0], t[1])
... 
c : 3
a : 4
b : 12

answered Jun 27 '12 at 14:58

number23_cn

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score 3 · Answer 4 · answered Jun 19 '21 at 08:22

3

Here's a solution with Python 3:

d = { "a":4, "c":3, "b":12 }
sorted(((v, k) for k, v in d.items()), reverse=True)

answered Jun 19 '21 at 08:22

jss367

4,759
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score 0 · Answer 5 · answered Jun 27 '12 at 14:46

0

d = { "a":4, "c":3, "b":12 }
for v in sorted( d.values() ):
    for key in d:
        if d[ key ] == v:
            print key, v
            break

answered Jun 27 '12 at 14:46

shiva

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This works but it loops X times on the whole dict, where X is the len() of the dict. It might waste resources. – Jean Coiron Dec 06 '19 at 14:27

Print a dict sorted by values

5 Answers5

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