Python dictionary copy() usage and example

Python dictionary methods

copy() method returns a shallow copy of the dictionary.

The syntax of copy() is:

dict.copy()

copy() parameters

copy() method has no parameters.

From the copy() return value

This method returns a shallow copy of the dictionary. It does not modify the original dictionary.

Example1: How does copying affect dictionaries?

original = {1: 'one',　2: 'two'}
new = original.copy()
print('Original dictionary: ', original)
print('Copy dictionary: ', new)

When running the program, the output is:

Original dictionary: {1: 'one',　2: 'two'}
Copy dictionary: {1: 'one',　2: 'two'}

The difference between using copy() method and = operator to copy a dictionary

When using the copy() method, a new dictionary will be created, which will fill with the copy of the references in the original dictionary.

When using the = operator, a new reference to the original dictionary will be created.

Example2: Use = operator to copy a dictionary

original = {1: 'one',　2: 'two'}
new = original
# Delete all elements from the list
new.clear()
print('new: ', new)
print('original: ', original)

When running the program, the output is:

new: {}
original: {

Here, when the new dictionary is cleared, the original dictionary is also cleared.

Example3: Use copy() to copy a dictionary

original = {1: 'one',　2: 'two'}
new = original.copy()
# Delete all elements from the list
new.clear()
print('new: ', new)
print('original: ', original)

When running the program, the output is:

new: {}
original: {1: 'one',　2: 'two'}

Here, after the new dictionary is cleared, the original dictionary remains unchanged.

Python dictionary methods