Python `len()` Function

Overview

The len() function in Python is a built-in function used to get the number of items in an object. It is commonly used with:

Strings
Lists
Tuples
Dictionaries
Other iterable or container types

Returns: An integer value representing the length or number of elements in the object.

Syntax

len(object)

Parameter: object can be a sequence (e.g., string, list, tuple) or a collection (e.g., dictionary, set) whose length is to be calculated.
Returns: An integer value indicating the number of items.

Examples of Usage

Example 1: Length of Various Data Types

# List
list_a = ['geeks', 'for', 'geeks', 2022]
print(len(list_a))  # Output: 4

# Tuple
tuple_b = (1, 2, 3, 4)
print(len(tuple_b))  # Output: 4

# Dictionary
dict_c = {"name": "Alice", "age": 30, "city": "New York"}
print(len(dict_c))  # Output: 3

Explanation:

For the list a, len(a) returns 4, indicating four items.
For the tuple b, len(b) returns 4, indicating four elements.
For the dictionary c, len(c) returns 3, counting the number of key-value pairs.

Example 2: Length of an Empty List

empty_list = []
print(len(empty_list))  # Output: 0

Explanation: As the list is empty, len() returns 0.

Example 3: Using `len()` with a Loop

list_d = [10, 20, 30, 40, 50]

for i in range(len(list_d)):
    print("Index:", i, "Value:", list_d[i])

Output:

Index: 0 Value: 10
Index: 1 Value: 20
Index: 2 Value: 30
Index: 3 Value: 40
Index: 4 Value: 50

Explanation: Here, range(len(list_d)) generates a sequence of indices, and list_d[i] accesses the list values by index.

Additional Information

The len() function is an essential part of Python's built-in functions and is frequently utilized in various programming scenarios, such as loops, conditional statements, and data structure manipulations.

For more examples and in-depth explanations, refer to GeeksforGeeks article on Python len() function.

Understanding Python's len() Function

Python len() Function