feat: add code demonstrating usage of map, filter, and reduce functions in Python

Author: soumadip-dev

14_Advance_Python/map_filter_reduce.py

@@ -0,0 +1,99 @@
+# map(), filter(), and reduce() in Python
+
+
+# ---------------------------
+# map()
+# ---------------------------
+# The map() function applies a given function to every element in an iterable
+# and returns a map object containing the transformed values.
+
+numbers_list = [1, 2, 3, 4, 5]
+
+
+# Function to calculate the square of a number
+def calculate_square(number):
+    return number * number
+
+
+# Convert the map object into a list to display all results
+squared_numbers_list = list(map(calculate_square, numbers_list))
+print("Squared numbers:", squared_numbers_list)
+
+
+# If we do not convert it to a list, map() returns an iterator.
+# We can access the values by iterating through it.
+
+squared_numbers_iterator = map(calculate_square, numbers_list)
+
+print("Squared numbers using iteration:")
+for squared_number in squared_numbers_iterator:
+    print(squared_number)
+
+
+# Using map() with a lambda function
+numbers_multiplied_by_two = list(map(lambda number: number * 2, numbers_list))
+print("Numbers multiplied by 2:", numbers_multiplied_by_two)
+
+
+# ---------------------------
+# filter()
+# ---------------------------
+# The filter() function selects elements from an iterable
+# that satisfy a specific condition.
+
+numbers_list = [3, 7, 10, 12, 4, 15]
+
+
+# Function to check whether a number is greater than 9
+def is_greater_than_nine(number):
+    return number > 9
+
+
+# Apply filter() to get numbers greater than 9
+numbers_greater_than_nine = list(filter(is_greater_than_nine, numbers_list))
+print("Numbers greater than 9:", numbers_greater_than_nine)
+
+
+# Using filter() with a lambda function
+numbers_greater_than_two = list(filter(lambda number: number > 2, numbers_list))
+print("Numbers greater than 2:", numbers_greater_than_two)
+
+
+# ---------------------------
+# reduce()
+# ---------------------------
+# The reduce() function repeatedly applies a function to elements
+# of an iterable until a single result remains.
+# reduce() must be imported from the functools module.
+
+from functools import reduce
+
+numbers_list = [1, 2, 3, 4, 5, 6]
+
+
+# Calculate the sum of numbers using a normal loop
+total_sum = 0
+for number in numbers_list:
+    total_sum = total_sum + number
+
+print("Sum calculated using a loop:", total_sum)
+
+
+# Function used by reduce() to add two numbers
+def add_numbers(first_number, second_number):
+    return first_number + second_number
+
+
+# Calculate the sum using reduce()
+sum_using_reduce = reduce(add_numbers, numbers_list)
+
+
+# Explanation of how reduce() works:
+# numbers_list = [1, 2, 3, 4, 5, 6]
+# Step 1: 1 + 2 = 3
+# Step 2: 3 + 3 = 6
+# Step 3: 6 + 4 = 10
+# Step 4: 10 + 5 = 15
+# Step 5: 15 + 6 = 21
+
+print("Sum calculated using reduce():", sum_using_reduce)

README.md

@@ -19,14 +19,16 @@ The repository includes examples and practice code for various Python concepts,
 - Comments and Escape Sequences
 - String Operations and Slicing
 - Conditional Statements
-- Control Flow and Loops
+- Loops and Control Flow
 - Functions and Lambda Functions
 - Recursive Functions
-- Python Modules (internal, external via pip, and custom-built)
+- Modules (Built-in, External using pip, and Custom Modules)
 - Variable Scope and Docstrings
-- list, touple sets, dictionary
-- OOPS(Class, Object, Inheritance, Composition, Polymorphism, Abstraction, Encapsulation, Method Resolution Order)
-- dunder methods
+- Lists, Tuples, Sets, and Dictionaries
+- Object-Oriented Programming (Classes, Objects, Inheritance, Composition, Polymorphism, Abstraction, Encapsulation, Method Resolution Order)
+- Dunder (Magic) Methods
+- Exception Handling
+- Map, Filter, and Reduce
 - Basic Python Programs and Exercises
 
 More topics will be added as I continue learning and practicing Python.