How to Get a List of Dictionary Keys in Python 2.7 and 3 ?

Returning Dictionary Keys as Lists in Python

In Python, accessing dictionary keys as a list often encounters differences between Python 2.7 and versions 3.3 and above. While Python 2.7 conveniently returns a list of keys with newdict.keys(), Python from 3.3 onwards encapsulates the keys in a dict_keys object.

To obtain a plain list of keys in Python 3, employ the list() function to convert the dict_keys object:

list(newdict.keys())

This will transform the encapsulated dict_keys into a standard list.

However, it's essential to consider whether this conversion truly matters. Python embraces duck typing, meaning if an object acts and responds like a list, its exact type becomes less significant. The dict_keys object can be subjected to list-like iterations:

for key in newdict.keys():
    print(key)

This performs key iteration just as well as a regular list. Notably, the dict_keys object lacks the ability to insert new elements via newdict[k] = v, but this may not be a necessity in many use cases.

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