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# Python – Filter and Double keys greater than K

• Last Updated : 04 May, 2020

Sometimes, while working with Python dictionaries, we can have the task of extracting certain keys after manipulation and filtration, both at once. This problem can be generalized for other values and operations as well. This has applications in many domains such as day-day programming and web development. Let’s discuss certain ways in which this task can be performed.

Method #1 : Using loop
This is one way to solve this problem. In this, we adopt brute force way to extract only filtered elements and store after doubling them.

 `# Python3 code to demonstrate working of ``# Filter and Double keys greater than K``# Using loop`` ` `# initializing dictionary``test_dict ``=` `{``'Gfg'` `: ``4``, ``'is'` `: ``2``, ``'best'``: ``3``, ``'for'` `: ``6``, ``'geeks'` `: ``1``}`` ` `# printing original dictionary``print``(``"The original dictionary : "` `+` `str``(test_dict))`` ` `# initializing K``K ``=` `2`` ` `# Filter and Double keys greater than K``# Using loop``res ``=` `dict``()``for` `key, val ``in` `test_dict.items():``    ``if` `val > K:``        ``res[key] ``=` `val ``*` `2`` ` `# printing result ``print``(``"The filtred dictionary : "` `+` `str``(res)) `
Output :

The original dictionary : {‘geeks’: 1, ‘for’: 6, ‘Gfg’: 4, ‘is’: 2, ‘best’: 3}
The filtred dictionary : {‘for’: 12, ‘Gfg’: 8, ‘best’: 6}

Method #2 : Using dictionary comprehension
This is yet another way to perform this task. In this, we perform task in similar way as above method, but in a more compact way.

 `# Python3 code to demonstrate working of ``# Filter and Double keys greater than K``# Using dictionary comprehension`` ` `# initializing dictionary``test_dict ``=` `{``'Gfg'` `: ``4``, ``'is'` `: ``2``, ``'best'``: ``3``, ``'for'` `: ``6``, ``'geeks'` `: ``1``}`` ` `# printing original dictionary``print``(``"The original dictionary : "` `+` `str``(test_dict))`` ` `# initializing K``K ``=` `2`` ` `# Filter and Double keys greater than K``# Using dictionary comprehension``res ``=` `{key : val ``*` `2` `for` `key, val ``in` `test_dict.items() ``if` `val > K}`` ` `# printing result ``print``(``"The filtred dictionary : "` `+` `str``(res)) `
Output :

The original dictionary : {‘geeks’: 1, ‘for’: 6, ‘Gfg’: 4, ‘is’: 2, ‘best’: 3}
The filtred dictionary : {‘for’: 12, ‘Gfg’: 8, ‘best’: 6}

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