Defaultdict Python – Nested defaultdicts in Python

Defaultdict Python :- Most times, the stuff required on this is very rare which you can only overcome while you learn over how to nest defaultdicts so as to properly save you from being bloated and confusing initialization code. The essence of this write up will cover; what are nested dictionaries? What is a defaultdicts, and when is it used? Finally how you create multi-level defaultdicts. I believe by now you must have gotten an idea of what is about been thought. So get prepared for the steps.Defaultdict Python

  • What nested dictionary is?

When you talk about a dictionary in python, it simply means a key-value map that might probably contain any type. To some extent, a “Nested” dictionary is simply a dictionary whose values are also dictionaries which many other people can equally use multiple levels. For example

Level_one  = {

          ‘level_two’ : {

                    ‘ Level_three’: {

                            ‘some_key’: ‘some_value’




However, you can access these values in the terminal dictionary via the following.

Level_one [‘level_two’] [‘level_three’] [‘some_key’]


  • The second part; what is Defaultdicts?

However, a defaultdicts is a dictionary having some added functionality. Now this allows you to specify a default type to return provide a key does not exist. Most times, if you try to access a non-existent key in a dictionary it will raise a keyError. But instead of raising an exception, it is better to return a default value. On that note, you can accomplish this with a powerful tool “defaultdicts. Now see how this works

From collections import defaultdicts

My_dict  =  defaultdicts(int)
with this, we have instantiated a defaultdicts and set the default type to int. what this is trying to explain is that we have try to access a key in my_dict which does not exist, it will then return the value of int( ) which is equally 0.

  • Nested defaultdict Python

Haven known what nested dictionaries and defaultdicts are talking about, you should be excited to get more on Nested defaultdicts.  This allows you to build complex dictionaries with a simple initialization. The only difference is that you just need to know the depth of your data structure before time. You should also know the default type of terminal values. To exercise this, at first we have to define our dictionary.

From collections import defaultdicts

My_dict  = defaultdict (lambda: defaultdicts (dict) )

For your information, lambda functions as the support to the first defauldict. Reason is because defauldict expects a callable (or None).


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