# Python – Extract Key’s Value, if Key Present in List and Dictionary

• Last Updated : 12 Aug, 2022

Given a list, dictionary and a Key K, print value of K from dictionary if key present in both, list and dictionary.

```Input : test_list = ["Gfg", "is", "Good", "for", "Geeks"],
test_dict = {"Gfg" : 5, "Best" : 6}, K = "Gfg"
Output : 5
Explanation : "Gfg" is present in list and has value 5 in dictionary.

Input : test_list = ["Good", "for", "Geeks"],
test_dict = {"Gfg" : 5, "Best" : 6}, K = "Gfg"
Output : None
Explanation : "Gfg" not present in List.```

Method #1 : Using all() + generator expression

The combination of the above functions offers one of the ways in which this problem can be solved. In this, we use all() to check for occurrence in both dictionary and list. If the result is true value is extracted from to result.

## Python3

 `# Python3 code to demonstrate working of ` `# Extract Key's Value, if Key Present in List and Dictionary` `# Using all() + list comprehension`   `# initializing list` `test_list ``=` `[``"Gfg"``, ``"is"``, ``"Good"``, ``"for"``, ``"Geeks"``]`   `# initializing Dictionary` `test_dict ``=` `{``"Gfg"` `: ``2``, ``"is"` `: ``4``, ``"Best"` `: ``6``}`   `# initializing K ` `K ``=` `"Gfg"`   `# printing original list and Dictionary` `print``(``"The original list : "` `+` `str``(test_list))` `print``(``"The original Dictionary : "` `+` `str``(test_dict))`   `# using all() to check for occurrence in list and dict` `# encapsulating list and dictionary keys in list ` `res ``=` `None` `if` `all``(K ``in` `sub ``for` `sub ``in` `[test_dict, test_list]):` `    ``res ``=` `test_dict[K]`   `# printing result ` `print``(``"Extracted Value : "` `+` `str``(res))`

Output

```The original list : ['Gfg', 'is', 'Good', 'for', 'Geeks']
The original Dictionary : {'Gfg': 2, 'is': 4, 'Best': 6}
Extracted Value : 2```

Method #2 : Using set() + intersection()

This is another way to check for the key’s presence in both the containers. In this, we compute the intersection of all values of list and dict keys and test for the Key’s occurrence in that.

## Python3

 `# Python3 code to demonstrate working of ` `# Extract Key's Value, if Key Present in List and Dictionary` `# Using set() + intersection()`   `# initializing list` `test_list ``=` `[``"Gfg"``, ``"is"``, ``"Good"``, ``"for"``, ``"Geeks"``]`   `# initializing Dictionary` `test_dict ``=` `{``"Gfg"` `: ``2``, ``"is"` `: ``4``, ``"Best"` `: ``6``}`   `# initializing K ` `K ``=` `"Gfg"`   `# printing original list and Dictionary` `print``(``"The original list : "` `+` `str``(test_list))` `print``(``"The original Dictionary : "` `+` `str``(test_dict))`   `# conversion of lists to set and intersection with keys ` `# using intersection` `res ``=` `None` `if` `K ``in` `set``(test_list).intersection(test_dict):` `    ``res ``=` `test_dict[K]`   `# printing result ` `print``(``"Extracted Value : "` `+` `str``(res))`

Output

```The original list : ['Gfg', 'is', 'Good', 'for', 'Geeks']
The original Dictionary : {'Gfg': 2, 'is': 4, 'Best': 6}
Extracted Value : 2```

Method #3: Using in operator

## Python3

 `# Python3 code to demonstrate working of` `# Extract Key's Value, if Key Present in List and Dictionary`   `# initializing list` `test_list ``=` `[``"Gfg"``, ``"is"``, ``"Good"``, ``"for"``, ``"Geeks"``]`   `# initializing Dictionary` `test_dict ``=` `{``"Gfg"` `: ``2``, ``"is"` `: ``4``, ``"Best"` `: ``6``}`   `# initializing K` `K ``=` `"Gfg"`   `# printing original list and Dictionary` `print``(``"The original list : "` `+` `str``(test_list))` `print``(``"The original Dictionary : "` `+` `str``(test_dict))`   `if` `K ``in` `test_dict.keys() ``and` `K ``in` `test_list:` `    ``res``=``test_dict[K]`   `# printing result` `print``(``"Extracted Value : "` `+` `str``(res))`

Output

```The original list : ['Gfg', 'is', 'Good', 'for', 'Geeks']
The original Dictionary : {'Gfg': 2, 'is': 4, 'Best': 6}
Extracted Value : 2```

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