How to check if a variable is a dictionary in Python

Question

How would you check if a variable is a dictionary in Python  For example  I d like it to loop through the values in the dictionary until it finds a dictionary  Then  loop through the one it finds  dict     abc    abc    def     ghi    ghi    jkl    jkl    for k  v in dict iteritems        if    check if v is a dictionary          for k  v in v iteritems                print k       v      else          print k       v

User · Accepted Answer

You could use if type ele  is dict or  use isinstance ele  dict  which would work if you had subclassed dict  d     abc    abc    def     ghi    ghi    jkl    jkl    for element in d values        if isinstance element  dict          for k  v in element items               print k     v

User · Answer

How would you check if a variable is a dictionary in Python    This is an excellent question  but it is unfortunate that the most upvoted answer leads with a poor recommendation  type obj  is dict    Note that you should also not use dict as a variable name - it s the name of the builtin object    If you are writing code that will be imported and used by others  do not presume that they will use the dict builtin directly - making that presumption makes your code more inflexible and in this case  create easily hidden bugs that would not error the program out   I strongly suggest  for the purposes of correctness  maintainability  and flexibility for future users  never having less flexible  unidiomatic expressions in your code when there are more flexible  idiomatic expressions     is is a test for object identity  It does not support inheritance  it does not support any abstraction  and it does not support the interface   So I will provide several options that do   Supporting inheritance   This is the first recommendation I would make  because it allows for users to supply their own subclass of dict  or a OrderedDict  defaultdict  or Counter from the collections module    if isinstance any object  dict    But there are even more flexible options   Supporting abstractions   from collections abc import Mapping  if isinstance any object  Mapping     This allows the user of your code to use their own custom implementation of an abstract Mapping  which also includes any subclass of dict  and still get the correct behavior   Use the interface  You commonly hear the OOP advice   program to an interface    This strategy takes advantage of Python s polymorphism or duck-typing    So just attempt to access the interface  catching the specific expected errors  AttributeError in case there is no  items and TypeError in case items is not callable  with a reasonable fallback - and now any class that implements that interface will give you its items  note  iteritems   is gone in Python 3    try      items   any object items   except  AttributeError  TypeError       non items behavior any object  else    no exception raised     for item in items        Perhaps you might think using duck-typing like this goes too far in allowing for too many false positives  and it may be  depending on your objectives for this code     Conclusion  Don t use is to check types for standard control flow  Use isinstance  consider abstractions like Mapping or MutableMapping  and consider avoiding type-checking altogether  using the interface directly

User · Answer

The OP did not exclude the starting variable  so for completeness here is how to handle the generic case of processing a supposed dictionary that may include items as dictionaries  Also following the pure Python 3 8  recommended way to test for dictionary in the above comments  from collections abc import Mapping  dict     abc    abc    def     ghi    ghi    jkl    jkl     def parse dict in dict        if isinstance in dict  Mapping           for k outer  v outer in in dict items                if isinstance v outer  Mapping                   for k inner  v inner in v outer items                        print k inner  v inner              else                  print k outer  v outer   parse dict dict

[python] How to check if a variable is a dictionary in Python?

Examples related to python

Examples related to dictionary