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Python - List Length and Count

Last Updated : May 01, 2025

In Python, you can determine the size of a list using the len() function and count specific elements using the count() method. In this chapter, we will learn how to find the length of a list, count occurrences of elements, and understand their usage through practical examples.

Getting Length of a List Using len()

The len() function is used to get the number of elements in a list.

Example

In this example, we are getting the total number of cities in a list using the len() function.

# Creating a list of cities
cities = ["New York", "London", "Paris", "Tokyo", "Sydney"]

# Getting the length of the list
length = len(cities)

# Displaying the length
print("Number of cities:", length)

The output of the above code would be:

Number of cities: 5

Counting Occurrences Using count()

The count() method returns the number of times a specified value appears in the list.

Example

In this example, we are counting how many times 'Paris' appears in the list of cities.

# Creating a list of cities with duplicate values
cities = ["New York", "Paris", "London", "Paris", "Tokyo", "Paris"]

# Counting the number of times 'Paris' appears
count_paris = cities.count("Paris")

# Displaying the count
print("'Paris' appears", count_paris, "times.")

The output of the above code would be:

'Paris' appears 3 times.

Using len() on Nested Lists

When using len() on a nested list, it returns the number of top-level elements (i.e., the outer list's length), not the total count of all inner elements.

Example

In this example, we are calculating the number of regions (sublists) in a nested city list.

# Creating a nested list of cities
cities = [
    ["New York", "Los Angeles"],
    ["London", "Manchester"],
    ["Tokyo", "Osaka"]
]

# Getting the number of regions
num_regions = len(cities)

# Displaying the number of regions
print("Number of regions:", num_regions)

The output of the above code would be:

Number of regions: 3

Counting All Items in a Nested List

To get the total number of all items in a nested list, you need to loop through each sublist and sum their lengths.

Example

In this example, we are using a loop to count the total number of cities in a nested list.

# Creating a nested list of cities
cities = [
    ["New York", "Los Angeles"],
    ["London", "Manchester"],
    ["Tokyo", "Osaka"]
]

# Calculating the total number of cities
total_cities = sum(len(region) for region in cities)

# Displaying the total count
print("Total number of cities:", total_cities)

The output of the above code would be:

Total number of cities: 6

Exercise

Select the correct option to complete each statement about getting the length and counting elements in a list in Python.

1. Which function is used to get the number of items in a list? --Select-- len() count() size()
2. Given my_list = [1, 2, 2, 3, 2], what does my_list.count(2) return? --Select-- 3 2 1
3. If items = ['a', 'b', 'c', 'a'], what is the result of items.count('a')? --Select-- 2 1 3