How can I use ChainMap in Python's collections module?

How can I use ChainMap in Python's collections module?

ChainMap is a class in the collections module that groups multiple dictionaries together. You can use it to manage multiple contexts.

Can you give me an example of how to create a ChainMap?

Sure! You can create a ChainMap by importing it from collections and passing multiple dictionaries to it. For example:

from collections import ChainMap

dict1 = {'a': 1, 'b': 2}
dict2 = {'b': 3, 'c': 4}

combined = ChainMap(dict1, dict2)
print(combined['b'])  # Output: 2

This will give priority to the first dictionary.

What happens if there are duplicate keys in the dictionaries?

In a ChainMap, if there are duplicate keys, the value from the first dictionary will be used. The subsequent dictionaries are only checked if the key is not found in the first.

Can I update the values in a ChainMap?

Yes, you can update values in a ChainMap, but it will only update the first dictionary in the ChainMap. If you want to update a value in a different dictionary, you need to access that dictionary directly.