Python 3 sort a dict by its values

Question

The only methods I found work for python2 or return only list of tuples   Is it possible to sort dictionary  e g    aa   3   bb   4   cc   2   dd   1   by its values   Order of sorted dictionary I want to achieve is from largest to smallest  I want results to look like this   bb 4 aa 3 cc 2 dd 1   And after sorting I want to store it into a text file

User · Answer

To sort a dictionary and keep it functioning as a dictionary afterwards, you could use OrderedDict from the standard library.

If that's not what you need, then I encourage you to reconsider the sort functions that leave you with a list of tuples. What output did you want, if not an ordered list of key-value pairs (tuples)?

User · Answer

Another way is to use a lambda expression  Depending on interpreter version and whether you wish to create a sorted dictionary or sorted key-value tuples  as the OP does   this may even be faster than the accepted answer  d     aa   3   bb   4   cc   2   dd   1  s   sorted d items    key lambda x  x 1   reverse True   for k  v in s      print k  v

User · Answer

You can sort by values in reverse order  largest to smallest  using a dictionary comprehension    k  d k  for k in sorted d  key d get  reverse True       b   4   a   3   c   2   d   1    If you want to sort by values in ascending order  smallest to largest    k  d k  for k in sorted d  key d get       d   1   c   2   a   3   b   4    If you want to sort by the keys in ascending order   k  d k  for k in sorted d       a   3   b   4   c   2   d   1    This works on CPython 3 6  and any implementation of Python 3 7  because dictionaries keep insertion order

User · Answer

itemgetter  see other answers  is  as I know  more efficient for large dictionaries but for the common case  I believe that d get wins  And it does not require an extra import    gt  gt  gt  d     aa   3   bb   4   cc   2   dd   1   gt  gt  gt  for k in sorted d  key d get  reverse True           k  d k        bb   4    aa   3    cc   2    dd   1    Note that alternatively you can set d   getitem   as key function which may provide a small performance boost over d get

User · Answer

To sort dictionary  we could make use of operator module  Here is the operator module documentation    import operator                              Importing operator module dc      aa   3   bb   4   cc   2   dd   1    Dictionary to be sorted  dc sort   sorted dc items   key   operator itemgetter 1  reverse   True  print dc sort   Output sequence will be a sorted list       bb   4     aa   3     cc   2     dd   1     If we want to sort with respect to keys  we can make use of   dc sort   sorted dc items   key   operator itemgetter 0  reverse   True    Output sequence will be       dd   1     cc   2     bb   4     aa   3

User · Answer

from collections import OrderedDict from operator import itemgetter      d     aa   3   bb   4   cc   2   dd   1  print OrderedDict sorted d items    key   itemgetter 1   reverse   True      prints  OrderedDict    bb   4     aa   3     cc   2     dd   1      Though from your last sentence  it appears that a list of tuples would work just fine  e g   from operator import itemgetter    d     aa   3   bb   4   cc   2   dd   1  for key  value in sorted d items    key   itemgetter 1   reverse   True       print key  value    which prints  bb 4 aa 3 cc 2 dd 1

[python] Python 3 sort a dict by its values

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