Dictionary keys, values, and items in Python

Introduction

Dictionaries store data in pairs: keys and values. You often need to get just the keys, just the values, or both together to work with the data.

When you want to list all the names (keys) in a phone book dictionary.

When you need all the phone numbers (values) from a contacts dictionary.

When you want to see each name and phone number together to print or process them.

When you want to check if a certain key exists in the dictionary.

When you want to loop through all pairs to update or analyze data.

Syntax

Python

dict.keys()
dict.values()
dict.items()

dict.keys() returns all the keys in the dictionary.

dict.values() returns all the values in the dictionary.

dict.items() returns pairs of (key, value) as tuples.

Examples

This shows all keys: 'apple' and 'banana'.

Python

my_dict = {'apple': 3, 'banana': 5}
keys = my_dict.keys()
print(keys)

This shows all values: 3 and 5.

Python

my_dict = {'apple': 3, 'banana': 5}
values = my_dict.values()
print(values)

This shows all key-value pairs as tuples.

Python

my_dict = {'apple': 3, 'banana': 5}
items = my_dict.items()
print(items)

Sample Program

This program creates a dictionary of fruits with quantities. It prints all keys, values, and key-value pairs.

Python

fruits = {'apple': 10, 'banana': 20, 'cherry': 30}

print('Keys:', list(fruits.keys()))
print('Values:', list(fruits.values()))
print('Items:', list(fruits.items()))

Important Notes

The keys(), values(), and items() methods return special views, so converting them to a list shows them clearly.

You can loop directly over these views in a for-loop without converting.

Summary

Dictionaries store data as key-value pairs.

Use keys() to get all keys, values() for all values, and items() for all pairs.

These methods help you access and work with dictionary data easily.