The order of keys in dictionaries

Question

Code   d     a   0   b   1   c   2  l   d keys    print l   This prints   a    c    b    I m unsure of how the method keys   determines the order of the keywords within l  However  I d like to be able to retrive the keywords in the  proper  order  The proper order of course would create the list   a    b    c

User · Answer

From http   docs python org tutorial datastructures html    The keys   method of a dictionary object returns a list of all the keys used in the dictionary  in arbitrary order  if you want it sorted  just apply the sorted   function to it

User · Answer

Although the order does not matter as the dictionary is hashmap  It depends on the order how it is pushed in   s    abbc  a    cbab   def load dict s       dict tmp          for ch in s          if ch in dict tmp keys                dict tmp ch   1         else              dict tmp ch    1     return dict tmp  dict a   load dict a  dict s   load dict s  print  for string  s  the keys are  s   s  dict s keys     print  for string  s  the keys are  s   a  dict a keys       output      for string abbc  the keys are dict keys   a    b    c        for string cbab  the keys are dict keys   c    b    a

User · Answer

Just sort the list when you want to use it   l   sorted d keys

User · Answer

You could use OrderedDict  requires Python 2 7  or higher   Also  note that OrderedDict   a   1   b  2   c  3   won t work since the dict you create with       has already forgotten the order of the elements  Instead  you want to use OrderedDict    a   1     b   2     c   3      As mentioned in the documentation  for versions lower than Python 2 7  you can use this recipe

User · Answer

gt  gt  gt  print sorted d keys      a    b    c     Use the sorted function  which sorts the iterable passed in   The  keys   method returns the keys in an arbitrary order

User · Answer

Python 3 7   In Python 3 7 0 the insertion-order preservation nature of dict objects has been declared to be an official part of the Python language spec  Therefore  you can depend on it   Python 3 6  CPython   As of Python 3 6  for the CPython implementation of Python  dictionaries maintain insertion order by default  This is considered an implementation detail though  you should still use collections OrderedDict if you want insertion ordering that s guaranteed across other implementations of Python   Python   2 7 and  lt 3 6  Use the collections OrderedDict class when you need a dict that  remembers the order of items inserted

[python] The order of keys in dictionaries

Examples related to python

Examples related to dictionary