Readably print out a python dict sorted by key

Question

I would like to print a python dictionary to a file using PrettyPrinter  for human readability  but have the dictionary be sorted by key in the output file to further improve readability  So   mydict     a  1   b  2   c  3  pprint mydict    currently prints to    b  2    c  3    a  1    I would like to PrettyPrint the dictionary but have it printed out sorted by key eg     a  1    b  2    c  3    What is the best way to do this

User · Answer

Another short oneliner   mydict     c   1   b   2   a   3  print  sorted mydict items     sep   n

User · Answer

The Python pprint module actually already sorts dictionaries by key  In versions prior to Python 2 5  the sorting was only triggered on dictionaries whose pretty-printed representation spanned multiple lines  but in 2 5 X and 2 6 X  all dictionaries are sorted   Generally  though  if you re writing data structures to a file and want them human-readable and writable  you might want to consider using an alternate format like YAML or JSON  Unless your users are themselves programmers  having them maintain configuration or application state dumped via pprint and loaded via eval can be a frustrating and error-prone task

User · Answer

I wrote the following function to print dicts  lists  and tuples in a more readable format   def printplus obj               Pretty-prints the object passed in                 Dict     if isinstance obj  dict           for k  v in sorted obj items                 print u  0    1   format k  v         List or tuple                 elif isinstance obj  list  or isinstance obj  tuple           for x in obj              print x        Other     else          print obj   Example usage in iPython    gt  gt  gt  dict example     c   1   b   2   a   3   gt  gt  gt  printplus dict example  a  3 b  2 c  1   gt  gt  gt  tuple example     1  2    3  4    5  6    7  8    gt  gt  gt  printplus tuple example   1  2   3  4   5  6   7  8

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Another alternative      gt  gt  gt  mydict     a  1   b  2   c  3   gt  gt  gt  import json   Then with python2      gt  gt  gt  print json dumps mydict  indent 4  sort keys True    python 2        a   1        b   2        c   3     or with python 3      gt  gt  gt  print json dumps mydict  indent 4  sort keys True     python 3        a   1        b   2        c   3

User · Answer

You could transform this dict a little to ensure that  as dicts aren t kept sorted internally   e g   pprint   key  mydict key   for key in sorted mydict keys

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An easy way to print the sorted contents of the dictionary  in Python 3    gt  gt  gt  dict example     c   1   b   2   a   3   gt  gt  gt  for key  value in sorted dict example items           print           format key  value        a   3 b   2 c   1   The expression dict example items   returns tuples  which can then be sorted by sorted      gt  gt  gt  dict example items   dict items    c   1     b   2     a   3     gt  gt  gt  sorted dict example items       a   3     b   2     c   1     Below is an example to pretty print the sorted contents of a Python dictionary s values   for key  value in sorted dict example items    key lambda d values  d values 1         print           format key  value

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Actually pprint seems to sort the keys for you under python2 5   gt  gt  gt  from pprint import pprint  gt  gt  gt  mydict     a  1   b  2   c  3   gt  gt  gt  pprint mydict    a   1   b   2   c   3   gt  gt  gt  mydict     a  1   b  2   c  3   d  4   e  5   gt  gt  gt  pprint mydict    a   1   b   2   c   3   d   4   e   5   gt  gt  gt  d   dict zip  kjihgfedcba  range 11     gt  gt  gt  pprint d    a   10    b   9    c   8    d   7    e   6    f   5    g   4    h   3    i   2    j   1    k   0    But not always under python 2 4   gt  gt  gt  from pprint import pprint  gt  gt  gt  mydict     a  1   b  2   c  3   d  4   e  5   gt  gt  gt  pprint mydict    a   1   c   3   b   2   e   5   d   4   gt  gt  gt  d   dict zip  kjihgfedcba  range 11     gt  gt  gt  pprint d    a   10    b   9    c   8    d   7    e   6    f   5    g   4    h   3    i   2    j   1    k   0   gt  gt  gt     Reading the source code of pprint py  2 5  it does sort the dictionary using  items   object items   items sort     for multiline or this for single line  for k  v in sorted object items       before it attempts to print anything  so if your dictionary sorts properly like that then it should pprint properly   In 2 4 the second sorted   is missing  didn t exist then  so objects printed on a single line won t be sorted   So the answer appears to be use python2 5  though this doesn t quite explain your output in the question   Python3 Update  Pretty print by sorted keys  lambda x  x 0     for key  value in sorted dict example items    key lambda x  x 0         print           format key  value     Pretty print by sorted values  lambda x  x 1     for key  value in sorted dict example items    key lambda x  x 1         print           format key  value

User · Answer

I had the same problem you had  I used a for loop with the sorted function passing in the dictionary like so   for item in sorted mydict       print item

[python] Readably print out a python dict() sorted by key

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