set.md

Python Sets and Practice Problems

Set Overview

• Definition: A set is a collection of unordered, unique, and immutable elements.
• Characteristics:
  • Avoids duplicate elements.
  • Elements are immutable, but the set itself is mutable (can be modified after creation).
  • Written using curly braces {} or the set() function.

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Examples and Set Operations

Creating a Set

collection = {1, 23, 4, 5, 6, 6, 0, "noushad"}
print(collection)  # Duplicate elements are removed
print(type(collection))
print(len(collection))  # Total number of unique elements

Empty Set

collection = set()
print(type(collection))  # Output: <class 'set'>

Adding and Removing Elements

collection.add(1)
collection.add(2)
collection.add("apna college")
collection.add((2, 5, 1))  # Adding a tuple (immutable)

collection.remove(2)  # Remove an element
print(collection)

collection.clear()  # Clear all elements
print(collection)

Set Methods

collection = {"hello", "world", "noushad", "ramim", "hello"}
print(collection.pop())  # Removes a random element

Set Operations

set1 = {1, 2, 3, 4, 5}
set2 = {4, 5, 6, 7, 8}

print(set1.union(set2))        # Union of two sets
print(set1.intersection(set2)) # Intersection of two sets

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Practice Problems

1. Storing Word Meanings

dictionary = {
    "cat": "a small animal",
    "table": ["a piece of furniture", "list of facts or figures"]
}
print(dictionary)

2. Finding Required Classrooms

• Given subjects: "python", "math", "science", "english", "history", "geography", "bangla", "religion", "physical education," "python", "math"

subjects = {
    "python", "math", "science", "english", "history", 
    "geography", "bangla", "religion", "physical education"
}
print(len(subjects))  # Output: Total unique subjects

3. Store Marks of 3 Subjects

marks = {}
marks.update({"phy": input("Enter Physics marks: ")})
marks.update({"chem": input("Enter Chemistry marks: ")})
marks.update({"math": input("Enter Math marks: ")})
print(marks)

4. Store 9 and 9.0 Separately

value = {
    ("float", 9.0),
    ("int", 9)
}
print(value)