Python tip N1 : simple ways to merge dictionaries in Python

In Python, dictionaries are commonly used to store key-value pairs. There are several ways to merge two or more dictionaries into a single dictionary. Here are some of the common methods used for this purpose:

Using the update() method: The update() method can be used to merge one dictionary into another. For example:

dict1 = {'a': 23, 'b': 24}
dict2 = {'c':32, 'j': 85}
dict1.update(dict2)
print(dict1)

The above code will give the following result

{'a': 23, 'b': 24, 'c': 32, 'j': 85}

Using the ** operator: The ** operator can also be used to merge dictionaries in Python. Here is the syntax for using it:

dict1 = {'a': 123, 'd': 562}
dict2 = {'b': 333, 'f': 232}
merged_dict = {**dict1, **dict2}
print(merged_dict)

The above code will give the following result

{'a': 123, 'd': 562, 'b': 333, 'f': 232}

Using the dict constructor: We can merge two dictionaries into one using the dict constructor. However, this method only works if the keys of the second dictionaries are strings. If not, we will have a TypeError.

dict1 = {'m': 1, 'l': 59}
dict2 = {'z': 3, 'c': 4}
merged_dict = dict(dict1, **dict2)
print(merged_dict)

The above code will give the following result

 {'m': 1, 'l': 59, 'z': 3, 'c': 4}

Using collections.ChainMap : ChainMap object helps to group multiple dictionaries together to create a single, updateable dictionary. Below is an example on how you can use it:

from collections import ChainMap
dict_1={'a': 15, 'b': 10}
dict_2={'c': 18,'d': 20}
merged_dict = ChainMap(dict_1, dict_2)
print(dict(merged_dict))

The above code will give the following result

{'c': 18, 'd': 20, 'a': 15, 'b': 10}