Iterate over a dictionary using for loops in Python

In Python, dictionaries are unordered collections of data values that are stored as key-value pairs. Dictionaries are often used to store data that is connected in some way, such as the words in a book and their definitions.

One common task when working with dictionaries is to iterate over the keys, values, or both in the dictionary. This can be done using a for loop.

Iterating Over the Keys in a Dictionary

To iterate over the keys in a dictionary, you can use the for loop as follows:

# Define a dictionary
d = {'cat': 'cute', 'dog': 'furry'}

# Iterate over the keys in the dictionary
for key in d:
    print(key)

This will output:

cat
dog

If you want to access the values in the dictionary while iterating over the keys, you can use the items() method to return a tuple of the key-value pairs in the dictionary:

# Iterate over the keys and values in the dictionary
for key, value in d.items():
    print(key, value)

This will output:

cat cute
dog furry

Iterating Over the Values in a Dictionary

To iterate over the values in a dictionary, you can use the values() method to return a list of the values in the dictionary, and then use a for loop to iterate over the list:

# Iterate over the values in the dictionary
for value in d.values():
    print(value)

This will output:

cute
furry

If you want to access the keys in the dictionary while iterating over the values, you can use the items() method as before to return a tuple of the key-value pairs:

# Iterate over the keys and values in the dictionary
for key, value in d.items():
    print(key, value)

This will output:

cat cute
dog furry

Iterating Over Both the Keys and Values in a Dictionary

To iterate over both the keys and values in a dictionary at the same time, you can use the items() method as shown above:

# Iterate over the keys and values in the dictionary
for key, value in d.items():
    print(key, value)

This will output:

cat cute
dog furry