add() method for set

my_set={'Alex','Ronald','John'}
my_set.add('Lewis')
print(my_set)

{'Ronald', 'John', 'Alex', 'Lewis'}

my_set={'a','b','c','x'}
my_set.add('c')
print(my_set)

{'a', 'x', 'c', 'b'}

unique_items = set()
for item in ['apple', 'banana', 'apple', 'orange']:
    unique_items.add(item)
print(unique_items)  # Output: {'banana', 'apple', 'orange'}

Comparison of add() vs update() in Python Sets

add(): Adds a single element to the set.

my_set = {1, 2}
my_set.add(3)
print(my_set)  # Output: {1, 2, 3}

update(): Adds multiple elements from an iterable (e.g., list, tuple).

my_set = {1, 2}
my_set.update([3, 4, 5])  # Adds multiple elements
print(my_set)  # Output: {1, 2, 3, 4, 5}

The add() method adds one element at a time, while update() can add several elements in one go.

Example 1: Adding Items Conditionally

my_set = {1, 2, 3}

# Add item only if it is greater than 10
item = 15
if item > 10:
    my_set.add(item)

print(my_set)

{1, 2, 3, 15}

Example 2: Using a Set to Track Unique Items

Sets are great for tracking unique items in a collection. For instance, let’s collect unique words from a list.

words = ["apple", "banana", "apple", "cherry", "banana", "date"]
unique_words = set()

for word in words:
    unique_words.add(word)

print(unique_words)

{'apple', 'banana', 'cherry', 'date'}

Example 3: Combining Sets with Addition

We can use the union method or the | operator to combine sets.

set_a = {1, 2, 3}
set_b = {3, 4, 5}

# Combine sets
combined_set = set_a | set_b

print(combined_set)

{1, 2, 3, 4, 5}

Use Case: Tracking Unique User Visits

Sets can be used to track unique users visiting a website or application:

visits = ["user1", "user2", "user1", "user3", "user2"]
unique_visits = set(visits)

print("Unique Users:", unique_visits)

Unique Users: {'user1', 'user2', 'user3'}

Use Case: Removing Duplicates from a List

Sets can help remove duplicates when you convert a list into a set.

numbers = [1, 2, 2, 3, 4, 4, 5]
unique_numbers = list(set(numbers))

print(unique_numbers)

[1, 2, 3, 4, 5]

Example 4: Adding Nested Sets (frozenset)

Python sets cannot directly include other sets because they are mutable. However, we can use frozenset, which is an immutable version of a set, for this purpose:

inner_set = frozenset({1, 2, 3})
outer_set = {4, 5}

# Adding frozenset
outer_set.add(inner_set)

print(outer_set)

{frozenset({1, 2, 3}), 4, 5}

Subhendu Mohapatra

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