How to pretty print nested dictionaries

Question

How can I pretty print a dictionary with depth of  4 in Python  I tried pretty printing with pprint    but it did not work   import pprint  pp   pprint PrettyPrinter indent 4  pp pprint mydict    I simply want an indentation    t   for each nesting  so that I get something like this   key1     value1     value2     key2        value1        value2   etc    How can I do this

User · Answer

This is what I came up with while working on a class that needed to write a dictionary in a .txt file:

@staticmethod
def _pretty_write_dict(dictionary):

    def _nested(obj, level=1):
        indentation_values = "\t" * level
        indentation_braces = "\t" * (level - 1)
        if isinstance(obj, dict):
            return "{\n%(body)s%(indent_braces)s}" % {
                "body": "".join("%(indent_values)s\'%(key)s\': %(value)s,\n" % {
                    "key": str(key),
                    "value": _nested(value, level + 1),
                    "indent_values": indentation_values
                } for key, value in obj.items()),
                "indent_braces": indentation_braces
            }
        if isinstance(obj, list):
            return "[\n%(body)s\n%(indent_braces)s]" % {
                "body": "".join("%(indent_values)s%(value)s,\n" % {
                    "value": _nested(value, level + 1),
                    "indent_values": indentation_values
                } for value in obj),
                "indent_braces": indentation_braces
            }
        else:
            return "\'%(value)s\'" % {"value": str(obj)}

    dict_text = _nested(dictionary)
    return dict_text

Now, if we have a dictionary like this:

some_dict = {'default': {'ENGINE': [1, 2, 3, {'some_key': {'some_other_key': 'some_value'}}], 'NAME': 'some_db_name', 'PORT': '', 'HOST': 'localhost', 'USER': 'some_user_name', 'PASSWORD': 'some_password', 'OPTIONS': {'init_command': 'SET foreign_key_checks = 0;'}}}

And we do:

print(_pretty_write_dict(some_dict))

We get:

{
    'default': {
        'ENGINE': [
            '1',
            '2',
            '3',
            {
                'some_key': {
                    'some_other_key': 'some_value',
                },
            },
        ],
        'NAME': 'some_db_name',
        'OPTIONS': {
            'init_command': 'SET foreign_key_checks = 0;',
        },
        'HOST': 'localhost',
        'USER': 'some_user_name',
        'PASSWORD': 'some_password',
        'PORT': '',
    },
}

User · Answer

As of what have been done  I don t see any pretty printer that at least mimics the output of the python interpreter with very simple formatting so here s mine    class Formatter object       def   init   self           self types              self htchar     t          self lfchar     n          self indent   0         self set formater object  self   class   format object          self set formater dict  self   class   format dict          self set formater list  self   class   format list          self set formater tuple  self   class   format tuple       def set formater self  obj  callback           self types obj    callback      def   call   self  value    args           for key in args              setattr self  key  args key           formater   self types type value  if type value  in self types else object          return formater self  value  self indent       def format object self  value  indent           return repr value       def format dict self  value  indent           items                 self lfchar   self htchar    indent   1    repr key                        self types type value key   if type value key   in self types else object   self  value key   indent   1              for key in value                   return    s          join items    self lfchar   self htchar   indent       def format list self  value  indent           items                 self lfchar   self htchar    indent   1     self types type item  if type item  in self types else object   self  item  indent   1              for item in value                   return    s          join items    self lfchar   self htchar   indent       def format tuple self  value  indent           items                 self lfchar   self htchar    indent   1     self types type item  if type item  in self types else object   self  item  indent   1              for item in value                   return    s          join items    self lfchar   self htchar   indent    To initialize it    pretty   Formatter     It can support the addition of formatters for defined types  you simply need to make a function for that like this one and bind it to the type you want with set formater    from collections import OrderedDict  def format ordereddict self  value  indent       items             self lfchar   self htchar    indent   1                  repr key            self types              type value key   if type value key   in self types else object            self  value key   indent   1                for key in value           return  OrderedDict   s           join items               self lfchar   self htchar   indent  pretty set formater OrderedDict  format ordereddict    For historical reasons  I keep the previous pretty printer which was a function instead of a class  but they both can be used the same way  the class version simply permit much more    def pretty value  htchar   t   lfchar   n   indent 0       nlch   lfchar   htchar    indent   1      if type value  is dict          items                 nlch   repr key           pretty value key   htchar  lfchar  indent   1              for key in value                   return    s          join items    lfchar   htchar   indent      elif type value  is list          items                 nlch   pretty item  htchar  lfchar  indent   1              for item in value                   return    s          join items    lfchar   htchar   indent      elif type value  is tuple          items                 nlch   pretty item  htchar  lfchar  indent   1              for item in value                   return    s          join items    lfchar   htchar   indent      else          return repr value    To use it     gt  gt  gt  a     list    a   b  1 2   dict    a  1 2  b    tuple    a   b  1 2   function  pretty  unicode  u  xa7    tuple   key    valid    gt  gt  gt  a   function    lt function pretty at 0x7fdf555809b0 gt    tuple     a    b   1  2    list     a    b   1  2    dict     a   1  2   b     unicode   u  xa7     tuple    key     valid    gt  gt  gt  print pretty a          function    lt function pretty at 0x7fdf555809b0 gt        tuple              a            b           1          2             list              a            b           1          2             dict              a   1          2   b              unicode   u  xa7         tuple    key     valid      Compared to other versions     This solution looks directly for object type  so you can pretty print almost everything  not only list or dict  Doesn t have any dependancy  Everything is put inside a string  so you can do whatever you want with it  The class and the function has been tested and works with Python 2 7 and 3 4  You can have all type of objects inside  this is their representations and not theirs contents that being put in the result  so string have quotes  Unicode string are fully represented       With the class version  you can add formatting for every object type you want or change them for already defined ones  key can be of any valid type  Indent and Newline character can be changed for everything we d like  Dict  List and Tuples are pretty printed

User · Answer

Another option with yapf     from pprint import pformat from yapf yapflib yapf api import FormatCode  dict example     1    1    2    2    3    1  2  3  4  5    4     1    1    2    2    3    1  2  3  4  5    dict string   pformat dict example  formatted code      FormatCode dict string   print formatted code    Output          1    1        2    2        3    1  2  3  4  5        4              1    1            2    2            3    1  2  3  4  5

User · Answer

I m a relative python newbie myself but I ve been working with nested dictionaries for the past couple weeks and this is what I had came up with   You should try using a stack  Make the keys from the root dictionary into a list of a list   stack     root keys           Result     root keys      Going in reverse order from last to first  lookup each key in the dictionary to see if its value is  also  a dictionary  If not  print the key then delete it  However if the value for the key is a dictionary  print the key then append the keys for that value to the end of the stack  and start processing that list in the same way  repeating recursively for each new list of keys   If the value for the second key in each list were a dictionary you would have something like this after several rounds      key 1   key 2     key 2 1   key 2 2     key 2 2 1   key 2 2 2     etc       The upside to this approach is that the indent is just  t times the length of the stack   indent     t    len stack    The downside is that in order to check each key you need to hash through to the relevant sub-dictionary  though this can be handled easily with a list comprehension and a simple for loop   path    li -1  for li in stack    The last key of every list of keys in the stack  sub   root for p in path      sub   sub p    if type sub     dict      stack append sub keys      And so on   Be aware that this approach will require you to cleanup trailing empty lists  and to delete the last key in any list followed by an empty list  which of course may create another empty list  and so on    There are other ways to implement this approach but hopefully this gives you a basic idea of how to do it   EDIT  If you don t want to go through all that  the pprint module prints nested dictionaries in a nice format

User · Answer

Here s a function I wrote based on what sth s comment  It s works the same as json dumps with indent  but I m using tabs instead of space for indents  In Python 3 2  you can specify indent to be a   t  directly  but not in 2 7   def pretty dict d       def pretty d  indent           for i   key  value  in enumerate d iteritems                 if isinstance value  dict                   print   0   1        format    t    indent  str key                   pretty value  indent 1                  if i    len d -1                      print   0     format    t    indent                  else                      print   0      format    t    indent              else                  if i    len d -1                      print   0   1      2    format    t    indent  str key   value                  else                      print   0   1      2     format    t    indent  str key   value      print         pretty d indent 1      print       Ex    gt  gt  gt  dict var     a  2   b    x  3   y    t1   4   t2  5     gt  gt  gt  pretty dict dict var         a    2        b              y                  t2    5                t1    4                      x    3

User · Answer

Sth  i sink that s pretty     def pretty d  indent 0       for key  value in d iteritems            if isinstance value  dict               print   t    indent       30s    n     str key  upper                pretty value  indent 1              print   t    indent         32         end of  s   n    str key  upper            elif isinstance value  list               for val in value                  print   t    indent       30s    n     str key  upper                    pretty val  indent 1                  print   t    indent         32         end of  s   n    str key  upper            else              print   t    indent       30s   s      str key  upper   str value

User · Answer

Here s something that will print any sort of nested dictionary  while keeping track of the  parent  dictionaries along the way    dicList   list    def prettierPrint dic  dicList   count   0 for key  value in dic iteritems        count  1     if str value      OrderedDict             value   None     if not isinstance value  dict           print str key           str value          print str key      was found in the following path            print dicList         print   n      elif isinstance value  dict           dicList append key          prettierPrint value  dicList      if dicList           if count    len dic                dicList pop                count   0  prettierPrint dicExample  dicList    This is a good starting point for printing according to different formats  like the one specified in OP  All you really need to do is operations around the Print blocks  Note that it looks to see if the value is  OrderedDict     Depending on whether you re using something from Container datatypes Collections  you should make these sort of fail-safes so the elif block doesn t see it as an additional dictionary due to its name  As of now  an example dictionary like   example dict     key1    value1                key2    value2                key3     key3a    value3a                 key4     key4a     key4aa    value4aa                                   key4ab    value4ab                                   key4ac    value4ac                          key4b    value4b     will print  key3a  value3a key3a was found in the following path    key3    key2  value2 key2 was found in the following path      key1  value1 key1 was found in the following path      key4ab  value4ab key4ab was found in the following path    key4    key4a    key4ac  value4ac key4ac was found in the following path    key4    key4a    key4aa  value4aa key4aa was found in the following path    key4    key4a    key4b  value4b key4b was found in the following path    key4      altering code to fit the question s format   lastDict   list   dicList   list   def prettierPrint dic  dicList       global lastDict     count   0     for key  value in dic iteritems            count  1         if str value      OrderedDict                 value   None         if not isinstance value  dict               if lastDict    dicList                  sameParents   True             else                  sameParents   False              if dicList and sameParents is not True                  spacing         len str dicList                   print dicList                 print spacing                  print str value               if dicList and sameParents is True                  print spacing                  print str value              lastDict   list dicList           elif isinstance value  dict               dicList append key              prettierPrint value  dicList           if dicList               if count    len dic                    dicList pop                    count   0   Using the same example code  it will print the following      key3            value3a   key4    key4a                     value4ab                   value4ac                   value4aa   key4            value4b   This isn t exactly what is requested in OP  The difference is that a parent n is still printed  instead of being absent and replaced with white-space  To get to OP s format  you ll need to do something like the following  iteratively compare dicList with the lastDict  You can do this by making a new dictionary and copying dicList s content to it  checking if i in the copied dictionary is the same as i in lastDict  and -- if it is -- writing whitespace to that i position using the string multiplier function

User · Answer

I m just returning to this question after taking sth s answer and making a small but very useful modification  This function prints all keys in the JSON tree as well as the size of leaf nodes in that tree   def print JSON tree d  indent 0       for key  value in d iteritems            print          indent   unicode key           if isinstance value  dict               print  print JSON tree value  indent 1          else              print      str type d key    split      1    -   str len unicode d key       It s really nice when you have large JSON objects and want to figure out where the meat is  Example    gt  gt  gt  print JSON tree JSON object  key1     value1   int - 5     value2   str - 16     key2        value1   str - 34        value2   list - 5623456   This would tell you that most of the data you care about is probably inside JSON object  key1    key2    value2   because the length of that value formatted as a string is very large

User · Answer

My first thought was that the JSON serializer is probably pretty good at nested dictionaries  so I d cheat and use that    gt  gt  gt  import json  gt  gt  gt  print json dumps   a  2   b    x  3   y    t1   4   t2  5                          sort keys True  indent 4         a   2       b              x   3           y                  t1   4               t2   5

User · Answer

Use this function   def pretty dict d  n 1       for k in d          print     n   k          try              pretty dict d k   n n 4          except TypeError              continue   Call it like this   pretty dict mydict

User · Answer

I took sth s answer and modified it slightly to fit my needs of a nested dictionaries and lists   def pretty d  indent 0       if isinstance d  dict           for key  value in d iteritems                print   t    indent   str key              if isinstance value  dict  or isinstance value  list                   pretty value  indent 1              else                  print   t     indent 1    str value      elif isinstance d  list           for item in d              if isinstance item  dict  or isinstance item  list                   pretty item  indent 1              else                  print   t     indent 1    str item      else          pass   Which then gives me output like    gt  gt  gt   xs schema      xmlns xs         http   www w3 org 2001 XMLSchema     xs redefine          schemaLocation             base xsd         xs complexType              name                 Extension             xs complexContent                 xs restriction                      base                         Extension                     xs sequence                         xs element                              name                                 Policy                              minOccurs                                 1                             xs complexType                                 xs sequence                                     xs element

User · Answer

As others have posted  you can use recursion dfs to print the nested dictionary data and call recursively if it is a dictionary  otherwise print the data   def print json data       if type data     dict              for k  v in data items                        print k                     print json v      else              print data

User · Answer

This class prints out a complex nested dictionary with sub dictionaries and sub lists          Recursive class to parse and print complex nested dictionary     class NestedDictionary object       def   init   self value           self value value      def print self depth           spacer  --------------------          if type self value   type dict                 for kk  vv in self value items                    if  type vv   type dict                          print spacer  depth  kk                      vvv  NestedDictionary vv                       depth depth 3                     vvv print depth                      depth depth-3                 else                      if  type vv   type list                              for i in vv                              vvv  NestedDictionary i                               depth depth 3                             vvv print depth                              depth depth-3                     else                          print spacer  depth  kk vv          Instatiate and execute - this prints complex nested dictionaries    with sub dictionaries and sub lists     something  is a complex nested dictionary  MyNest NestedDictionary weather com result  MyNest print 0

User · Answer

By this way you can print it in pretty way for example your dictionary name is yasin import json  print  json dumps yasin  indent 2    or  safer  print  json dumps yasin  indent 2  default str

User · Answer

One of the most pythonic ways for that is to use the already build pprint module   The argument that you need for define the print depth is as you may expect depth  import pprint pp   pprint PrettyPrinter depth 4  pp pprint mydict    That s it

User · Answer

I m not sure how exactly you want the formatting to look like  but you could start with a function like this   def pretty d  indent 0      for key  value in d items          print   t    indent   str key         if isinstance value  dict            pretty value  indent 1        else           print   t     indent 1    str value

User · Answer

I wrote this simple code to print the general structure of a json object in Python    def getstructure data  tab   0       if type data  is dict          print     tab                for key in data              print     tab          key                   getstructure data key   tab 4          print     tab                    elif type data  is list and len data   gt  0          print     tab               getstructure data 0   tab 4          print     tab                   print     tab         the result for the following data  a     list    a   b  1 2   dict    a  1 2  b    tuple    a   b  1 2   function   p   unicode  u  xa7    tuple   key    valid   getstructure a    is very compact and looks like this       function    tuple    list                          dict              a        2          unicode      tuple    key

User · Answer

You could try YAML via PyYAML   Its output can be fine-tuned   I d suggest starting with the following   print yaml dump data  allow unicode True  default flow style False   The result is very readable  it can be also parsed back to Python if needed   Edit   Example    gt  gt  gt  import yaml  gt  gt  gt  data     a  2   b    x  3   y    t1   4   t2  5     gt  gt  gt  print yaml dump data  default flow style False  a  2 b    x  3   y      t1  4     t2  5

User · Answer

You can use print-dict from print dict import pd  dict1          key    value      pd dict1   Output         key    value      Output of this Python code         one    value-one        two    value-two        three    value-three        four              1    1            2    2            3    1  2  3  4  5            4                  method    lt function custom method at 0x7ff6ecd03e18 gt                tuple    1  2                unicode                     ten    value-ten                eleven    value-eleven                3    1  2  3  4                        object1    lt   main   Object1 object at 0x7ff6ecc588d0 gt        object2    lt Object2 info gt        class    lt class    main   Object1  gt      Install    pip install print-dict   Disclosure  I m the author of print-dict

User · Answer

pout can pretty print anything you throw at it  for example  borrowing data from another answer    data     a  2   b    x  3   y    t1   4   t2  5    pout vs data    would result in output printed to the screen like          a   2       b                  y                          t2   5               t1   4                     x   3           or you can return the formatted string output of your object   v   pout s data    Its primary use case is for debugging so it doesn t choke on object instances or anything and it handles unicode output as you would expect  works in python 2 7 and 3   disclosure  I m the author and maintainer of pout

User · Answer

I had to pass the default parameter as well  like this  print json dumps my dictionary  indent 4  default str    and if you want the keys sorted  then you can do  print json dumps my dictionary  sort keys True  indent 4  default str    in order to fix this type error  TypeError  Object of type  datetime  is not JSON serializable  which caused by datetimes being some values in the dictionary

User · Answer

From this link   def prnDict aDict  br   n   html 0              keyAlign  l     sortKey 0              keyPrefix       keySuffix                 valuePrefix     valueSuffix                 leftMargin 0    indent 1            return a string representive of aDict in the following format             key1  value1       key2  value2                   Spaces will be added to the keys to make them have same width   sortKey  set to 1 if want keys sorted  keyAlign  either  l  or  r   for left  right align  respectively  keyPrefix  keySuffix  valuePrefix  valueSuffix  The prefix and    suffix to wrap the keys or values  Good for formatting them    for html document for example  keyPrefix   lt b gt    keySuffix   lt  b gt         Note  The keys will be padded with spaces to have them          equally-wide  The pre- and suffix will be added OUTSIDE          the entire width  html  if set to 1  all spaces will be replaced with   amp nbsp    and       the entire output will be wrapped with   lt code gt   and   lt  code gt    br  determine the carriage return  If html  it is suggested to set     br to   lt br gt    If you want the html source code eazy to read      set br to   lt br gt  n   version  04b52 author   Runsun Pan require  odict     an ordered dict  if you want the keys sorted           Dave Benjamin           http   aspn activestate com ASPN Cookbook Python Recipe 161403              if aDict            ------------------------------ sort key         if sortKey              dic   aDict copy               keys   dic keys               keys sort               aDict   odict               for k in keys                  aDict k    dic k            ------------------- wrap keys with      quotes  if str         tmp                 ks    type x   str and    s   x or x for x in aDict keys              ------------------- wrap values with      quotes  if str         vs    type x   str and    s   x or x for x in aDict values              maxKeyLen   max  len str x   for x in ks            for i in range len ks                  -------------------------- Adjust key width             k    1              str ks i   ljust maxKeyLen                    keyAlign   r   str ks i   rjust maxKeyLen    1               v   vs i                      tmp append      indent    s s s  s s s                              keyPrefix  k  keySuffix                          valuePrefix v valueSuffix            tmp -1    tmp -1   -1    remove the     in the last item         tmp append               if leftMargin            tmp         leftMargin   x for x in tmp            if html              return   lt code gt  s lt  code gt    br join tmp  replace       amp nbsp            else              return br join tmp           else          return           Example    gt  gt  gt  a   C   2   B   1   E   4   3  5   0    gt  gt  gt  print prnDict a      C     2    B     1    E     4    3  5  0     gt  gt  gt  print prnDict a  sortKey 1      B     1    C     2    E     4    3  5  0     gt  gt  gt  print prnDict a  keyPrefix   lt b gt    keySuffix   lt  b gt        lt b gt  C     lt  b gt  2    lt b gt  B     lt  b gt  1    lt b gt  E     lt  b gt  4    lt b gt  3  5  lt  b gt  0     gt  gt  gt  print prnDict a  html 1   lt code gt    amp nbsp  C  amp nbsp  amp nbsp  amp nbsp  2   amp nbsp  B  amp nbsp  amp nbsp  amp nbsp  1   amp nbsp  E  amp nbsp  amp nbsp  amp nbsp  4   amp nbsp  3  amp nbsp 5  0   lt  code gt    gt  gt  gt  b   car    6  6  12    about    15  9  6    bookKeeper    9  9  15     gt  gt  gt  print prnDict b  sortKey 1      about        15  9  6     bookKeeper   9  9  15     car          6  6  12      gt  gt  gt  print prnDict b  keyAlign  r              car   6  6  12          about   15  9  6     bookKeeper   9  9  15

[python] How to pretty print nested dictionaries?

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