How to convert a nested OrderedDict to Dict in Python?

Python is a popular programming language that is widely used for various applications, including web development, data science, and machine learning. Its simplicity, flexibility, and ease of use make it an excellent choice for developers of all levels. One of the features that make Python stand out is the OrderedDict class, which is a dictionary subclass that remembers the order that items were inserted. However, in some cases, we may need to convert a nested OrderedDict to a regular dict to facilitate further processing of the data.

In this tutorial, we will explain what a nested OrderedDict is and why it may be necessary to convert it to a regular dict. We will walk you through the process of converting a nested OrderedDict to a dict using a recursive approach. We will also provide examples of how to use the code and explain the benefits of using a regular dict over a nested OrderedDict. So, let's dive into the next section of the article to learn more about converting a nested OrderedDict to a dict.

What is an OrderedDict?

An OrderedDict is a subclass of a regular dictionary in which the order of items is maintained. This means that the items in an OrderedDict are stored in the order in which they were added to the dictionary.

Now let's move on to Nested OrderedDict. As the name suggests, a Nested OrderedDict is simply an OrderedDict within another OrderedDict. This means that the values in the outer OrderedDict are themselves OrderedDicts. This is a useful data structure for representing nested or hierarchical data.

Here's an example of a Nested OrderedDict:

from collections import OrderedDict

nested_odict = OrderedDict({
    'Name': 'John Doe',
    'Age': 25,
    'Contact': OrderedDict({
        'Email': 'johndoe@example.com',
        'Phone': '123-456-7890'
    }),
    'Address': OrderedDict({
        'Street': '123 Main St',
        'City': 'Anytown',
        'State': 'CA',
        'Zip': '12345'
    })
})

In the above example, we have created a Nested OrderedDict that represents information about a person, including their name, age, contact information, and address. The 'Contact' and 'Address' keys have values that are themselves OrderedDicts.

The structure of the Nested OrderedDict can be visualized as follows:

{
    'Name': 'John Doe',
    'Age': 25,
    'Contact': {
        'Email': 'johndoe@example.com',
        'Phone': '123-456-7890'
    },
    'Address': {
        'Street': '123 Main St',
        'City': 'Anytown',
        'State': 'CA',
        'Zip': '12345'
    }
}

Now that we’ve learned about the structure of Nested OrderedDict, let understand how to convert this Nested OrderedDict to a regular dict using a recursive approach.

How to convert a nested OrderedDict to dict?

One way to convert a Nested OrderedDict to a dict is by using recursion. Recursion is a programming technique that involves a function calling itself. In this case, we can write a function that recursively calls itself to convert each nested OrderedDict to a regular dict.

Here's an example of how to implement the recursion to convert a Nested OrderedDict to a dict:

def nested_odict_to_dict(nested_odict):
   # Convert the nested ordered dictionary into a regular dictionary and store it in the variable "result".
   result = dict(nested_odict)

   # Iterate through each key-value pair in the dictionary.
   for key, value in result.items():

       # Check if the value is an instance of the OrderedDict class.
       if isinstance(value, OrderedDict):
           # If the value is an instance of the OrderedDict class, recursively call the function on that value and store the returned dictionary in the "result" dictionary.
           result[key] = nested_odict_to_dict(value)
   return result

In the above code, we first create a regular dict from the Nested OrderedDict using the built-in dict() function. We then loop through each key-value pair in the dict and check if the value is an instance of OrderedDict. If it is, we call the same function recursively on that value and replace the value in the original dict with the returned regular dict.

Let's break down the code and understand how it works:

result = dict(nested_odict)

This line creates a new dictionary (result) by converting the ordered dictionary passed in (nested_odict) to a regular dictionary.

for key, value in result.items():
    if isinstance(value, OrderedDict):
        result[key] = nested_odict_to_dict(value)

This loop iterates through all the items in the result dictionary. For each key-value pair, it checks if the value is an ordered dictionary. If it is, the function recursively calls itself, passing in the ordered dictionary as an argument, and replaces the value in result with the returned dictionary.

Let’s understand it with the help of an example now.

Example of Converting Nested OrderedDict to Dict

Let's use the same Nested OrderedDict that we saw earlier and convert it to a regular dict using the nested_odict_to_dict() function:

from collections import OrderedDict

nested_odict = OrderedDict({
    'Name': 'John Doe',
    'Age': 25,
    'Contact': OrderedDict({
        'Email': 'johndoe@example.com',
        'Phone': '123-456-7890'
    }),
    'Address': OrderedDict({
        'Street': '123 Main St',
        'City': 'Anytown',
        'State': 'CA',
        'Zip': '12345'
    })
})

regular_dict = nested_odict_to_dict(nested_odict)
print(regular_dict)

This above code snipper creates an ordered dictionary nested_odict with several levels of nesting, and then calls a function nested_odict_to_dict to convert it to a regular nested dictionary. The output of the this code will be a nested dictionary with the same keys and values as the original ordered dictionary nested_odict, but without the ordering guarantee.

Output

{
    'Name': 'John Doe',
    'Age': 25,
    'Contact': {
        'Email': 'johndoe@example.com',
        'Phone': '123-456-7890'
    },
    'Address': {
        'Street': '123 Main St',
        'City': 'Anytown',
        'State': 'CA',
        'Zip': '12345'
    }
}

As you can see, the Nested OrderedDict has been successfully converted to a regular dict using the nested_odict_to_dict() function.

Conclusion

In this article, we have discussed how to convert a nested OrderedDict to a regular dict using a recursive approach. We explained what an OrderedDict is and what a nested OrderedDict is. We also provided an example of a Nested OrderedDict that represents information about a person. To convert a nested OrderedDict to a regular dict, we used recursion to write a function that calls itself to convert each nested OrderedDict to a regular dict. We also provided an example of how to use the function to convert the Nested OrderedDict we created earlier to a regular dict. By converting a Nested OrderedDict to a regular dict, we can simplify the processing of data and perform various operations with greater ease.