# Python | K modulo on each Dictionary Key

• Last Updated : 02 Feb, 2023

Sometimes, while working with dictionaries, we might come across a problem in which we require to perform a particular operation on each value of keys like K modulo on each key. This type of problem can occur in web development domain. Letâ€™s discuss certain ways in which this task can be performed. Method #1 : Using loop This is the naive method in which this task can be performed. In this we simply run a loop to traverse each key in dictionary and perform the desired operation of K modulo.

## Python3

 `# Python3 code to demonstrate working of``# K modulo on each Dictionary Key``# Using loop` `# Initialize dictionary``test_dict ``=` `{``'gfg'` `: ``6``, ``'is'` `: ``4``, ``'best'` `: ``7``}` `# printing original dictionary``print``("The original dictionary : " ``+` `str``(test_dict))` `# initializing K``K ``=` `4` `# Using loop``# K modulo on each Dictionary Key``for` `key ``in` `test_dict:``    ``test_dict[key] ``%``=` `4` `# printing result``print``("The dictionary after mod K each key's value : " ``+` `str``(test_dict))`

Output :

```The original dictionary : {'is': 4, 'best': 7, 'gfg': 6}
The dictionary after mod K each key's value : {'is': 0, 'best': 3, 'gfg': 2}```

Method #2 : Using update() + dictionary comprehension An alternate one-liner to perform this task, the combination of above functions can be used to perform this particular task. The update function is used to perform the % K over the dictionary.

## Python3

 `# Python3 code to demonstrate working of``# K modulo on each Dictionary Key``# Using update() + dictionary comprehension` `# Initialize dictionary``test_dict ``=` `{``'gfg'` `: ``6``, ``'is'` `: ``4``, ``'best'` `: ``7``}` `# printing original dictionary``print``("The original dictionary : " ``+` `str``(test_dict))` `# initializing K``K ``=` `4` `# Using update() + dictionary comprehension``# K modulo on each Dictionary Key``test_dict.update((x, y ``%` `K) ``for` `x, y ``in` `test_dict.items())` `# printing result``print``("The dictionary after mod K each key's value : " ``+` `str``(test_dict))`

Output :

```The original dictionary : {'is': 4, 'best': 7, 'gfg': 6}
The dictionary after mod K each key's value : {'is': 0, 'best': 3, 'gfg': 2}```

Method #3 : Using dictionary comprehension

## Python3

 `# Method #3 : Using dictionary comprehension` `# Python3 code to demonstrate working of``# K modulo on each Dictionary Key``# Using dictionary comprehension``  ` `# Initialize dictionary``test_dict ``=` `{``'gfg'` `: ``6``, ``'is'` `: ``4``, ``'best'` `: ``7``}``  ` `# printing original dictionary``print``(``"The original dictionary : "` `+` `str``(test_dict))``  ` `# initializing K``K ``=` `4``  ` `# Using map() + dictionary comprehension``# K modulo on each Dictionary Key``test_dict ``=` `{key: value ``%` `K ``for` `key, value ``in` `test_dict.items()}``  ` `# printing result``print``(``"The dictionary after mod K each key's value : "` `+` `str``(test_dict))`

Output

```The original dictionary : {'gfg': 6, 'is': 4, 'best': 7}
The dictionary after mod K each key's value : {'gfg': 2, 'is': 0, 'best': 3}
```

# Time complexity : O(n), n is the number of keys in the dictionary.
# Space complexity : O(n), n is the number of keys in the dictionary.

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