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Python Dictionary clear() Function

The Dictionary clear() method removes all items from the dictionary.

note

This method does not return anything: it modifies the dictionary in place, leaving it empty.

Syntax​

my_dictionary.clear()

clear() Parameters​

Python Dictionary clear() function does not take any parameters.

clear() Return Value​

Python Dictionary clear() function does not return any value.

Examples​

Example 1: Clear a Dictionary​

Let's use clear() to remove all the items from the dictionary:

my_dict = {1: "Tutorial",  2: "Reference", 3:"tutorialreference.com"}

my_dict.clear()
print(my_dict) # {}

output

{}

Example 2: Clear a list of dictionaries​

Let's use clear() method to remove all key-value pairs from each dictionary within a list. By iterating over each dictionary in list_of_dict and calling clear() on each, the contents of each dictionary are removed, resulting in a list of empty dictionaries.

# List of dictionaries
list_of_dict = [
    {'Name': 'Tom', 'Age':  35},
    {'Name': 'David', 'Age':  25},
    {'Name': 'Anna', 'Age':  23},
    {'Name': 'Ryan', 'Age':  28},
]

print('Original Dictionary:')
print(list_of_dict)

# Clear all dictionaries in a list of dictionaries
for elem in list_of_dict:
    elem.clear()

print('Updated Dictionary:')
print(list_of_dict)

output

Original Dictionary:
[{'Name': 'Tom', 'Age': 35}, {'Name': 'David', 'Age': 25}, {'Name': 'Anna', 'Age': 23}, {'Name': 'Ryan', 'Age': 28}]
Updated Dictionary:
[{}, {}, {}, {}]

clear() vs Assigning an Empty Dictionary​

Assigning an empty dictionary my_dictionary = {} is not same as my_dictionary.clear().

For example,

old_dict = {'name': 'Tom', 'age': 25}
new_dict = old_dict
old_dict = {}

print(old_dict) # Output: {}
print(new_dict) # Output: {'age': 25, 'name': 'Tom'}

output

{}
{'name': 'Tom', 'age': 25}

The difference is that old_Dict = {} does not empty the dictionary in-place, it just overwrites the variable with a different dictionary which happens to be empty. If anyone else like new_Dict had a reference to the original dictionary, that remains as-is.

In contrast, the clear() method empties the dictionary in-place. Thus, all references are also cleared.

old_dict = {'name': 'Tom', 'age': 25}
new_dict = old_dict
old_dict.clear()
print(old_dict) # Output: {}
print(new_dict) # Output: {}

output

{}
{}

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