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# Python – Flatten and remove keys from Dictionary

• Last Updated : 01 Aug, 2020

Given a dictionary, perform flattening and removal of certain dictionary keys.

Input : test_dict = {‘a’: 14, ‘b’: 16, ‘c’: {‘d’: {‘e’: 7}}}, rem_keys = [“c”, “a”, “d”]
Output : {‘b’: 16, ‘e’: 7}
Explanation : All “c”, “a” and “d” has been removed.

Input : test_dict = {‘a’: 14, ‘b’: 16, ‘c’: {‘d’: {‘e’: 7}}}, rem_keys = [“c”, “d”, “e”]
Output : {‘a’: 14, ‘b’: 16}
Explanation : All “c”, “e” and “d” has been removed.

Method : Using recursion + isinstance() + loop

The combination of above functions can be used to solve this problem. In this, we check for dictionary as instance for nested dictionary using isinstance() and recur each time for inner dictionary. The loop is used to iterate for keys.

## Python3

 `# Python3 code to demonstrate working of ``# Flatten and remove keys from Dictonary``# Using loop + recursion + isinstance()`` ` `# function to compute removal and flattening``def` `hlper_fnc(test_dict, rem_keys):``    ``if` `not` `isinstance``(test_dict, ``dict``):``        ``return` `test_dict ``    ``res ``=` `{}``     ` `    ``for` `key, val ``in` `test_dict.items():``        ``rem ``=` `hlper_fnc(val, rem_keys)``         ` `        ``# performing removal``        ``if` `key ``not` `in` `rem_keys:``            ``res[key] ``=` `rem``        ``else``:``            ``if` `isinstance``(rem, ``dict``):``                ``res.update(rem)``    ``return` `res`` ` `# initializing dictionary``test_dict ``=` `{``'a'``: ``14``, ``'b'``: ``16``, ``'c'``: {``'d'``: {``'e'``: ``7``}}}`` ` `# printing original dictionary``print``(``"The original dictionary is : "` `+` `str``(test_dict))`` ` `# initializing removal keys ``rem_keys ``=` `[``"c"``, ``"d"``]`` ` `# calling helper function for task ``res ``=` `hlper_fnc(test_dict, rem_keys)`` ` `# printing result ``print``(``"The removed and flattened dictionary : "` `+` `str``(res)) `
Output

The original dictionary is : {‘a’: 14, ‘b’: 16, ‘c’: {‘d’: {‘e’: 7}}}
The removed and flattened dictionary : {‘a’: 14, ‘b’: 16, ‘e’: 7}

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