# Python – Merge List value Keys to Matrix

• Last Updated : 10 May, 2020

Sometimes, while working with Python dictionary, we can have a problem in which we need to perform the merger of certain keys in dictionary. In this, we tend to form a matrix of resultant singular key. This kind of problem can have applications in data domains. Let’s discuss certain way in which this task can be performed.

Input : test_dict = {‘Maths’: [1, 2], ‘gfg’: [4, 5], ‘CS’: [6]}
Output : {‘merge_key’: [[4, 5], [6], [1, 2]]}

Input : test_dict = {‘Maths’: [1], ‘gfg’: [4], ‘CS’: [9]}
Output : {‘merge_key’: [[4], [9], [1]]}

Method : Using loop +` pop()`
This task can be performed using brute force manner. In this, we iterate the keys and remove the keys using pop, reinitialize them after merging into a matrix.

 `# Python3 code to demonstrate working of ``# Merge List value Keys to Matrix``# Using loop + pop()`` ` `# initializing dictionary``test_dict ``=` `{``'gfg'` `: [``4``, ``5``, ``6``], ``             ``'is'` `: [``8``, ``8``, ``9``],``             ``'CS'` `: [``1``, ``3``, ``8``], ``             ``'Maths'` `: [``1``, ``2``]}`` ` `# printing original dictionary``print``(``"The original dictionary : "` `+` `str``(test_dict))`` ` `# initializing list ``que_list ``=` `[``'gfg'``, ``'CS'``, ``'Maths'``]`` ` `# Merge List value Keys to Matrix``# Using loop + pop()``new_data ``=` `[test_dict.pop(ele) ``for` `ele ``in` `que_list]``test_dict[``"merge_key"``] ``=` `new_data`` ` `# printing result ``print``(``"The dictionary after merging : "` `+` `str``(test_dict)) `
Output :

The original dictionary : {‘is’: [8, 8, 9], ‘gfg’: [4, 5, 6], ‘Maths’: [1, 2], ‘CS’: [1, 3, 8]}
The dictionary after merging : {‘is’: [8, 8, 9], ‘merge_key’: [[4, 5, 6], [1, 3, 8], [1, 2]]}

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