Count the Number of Elements in a Python List

The len() function can be used to count the number of elements in a Python list:

`len(my_list)`

3 Examples of Counting the Number of Elements in a List

Example 1: List that Contains Strings

To start with a simple example, create a list that contains 5 names:

`names_list = ["Jeff", "Ben", "Maria", "Sophia", "Rob"]print(names_list)`

Run the script above, and you’ll get the following list:

``['Jeff', 'Ben', 'Maria', 'Sophia', 'Rob']``

You can then use the len() function in order to count the number of elements in the list:

`names_list = ["Jeff", "Ben", "Maria", "Sophia", "Rob"]number_of_elements = len(names_list)print(number_of_elements)`

Once you run the script in Python, you’ll get the following count:

``5``

Extend the list by additional 3 names, and then recount the number of elements:

`names_list = ["Jeff", "Ben", "Maria", "Sophia", "Rob"]names_list.extend(["Laura", "Elizabeth", "Justin"])number_of_elements = len(names_list)print(number_of_elements)`

Here is the new count:

``8``

Example 2: List that Contains Numeric Data

Now create a list with numeric data:

`numbers_list = [7, 22, 35, 28, 42, 15, 30, 11, 24, 17]print(numbers_list)`

Here is the list that you’ll get:

``[7, 22, 35, 28, 42, 15, 30, 11, 24, 17]``

Use the len() function to count the number of elements in the list:

`numbers_list = [7, 22, 35, 28, 42, 15, 30, 11, 24, 17]number_of_elements = len(numbers_list)print(number_of_elements)`

The result:

``10``

Example 3: List of Lists

What if you want to count the number of elements in a list of lists?

For instance, let’s create the following list of lists:

`people_list = [    ["Jon", "Smith", 21],    ["Mark", "Brown", 38],    ["Maria", "Lee", 42],    ["Jill", "Jones", 28],    ["Jack", "Ford", 55],]print(people_list)`

You’ll now see this list of lists:

``[['Jon', 'Smith', 21], ['Mark', 'Brown', 38], ['Maria', 'Lee', 42], ['Jill', 'Jones', 28], ['Jack', 'Ford', 55]]``

Before you count all the elements, you’ll need to flatten the list of lists as follows:

`people_list = [    ["Jon", "Smith", 21],    ["Mark", "Brown", 38],    ["Maria", "Lee", 42],    ["Jill", "Jones", 28],    ["Jack", "Ford", 55],]flat_people_list = [i for x in people_list for i in x]print(flat_people_list)`

Here is how the flatten list would look like:

``['Jon', 'Smith', 21, 'Mark', 'Brown', 38, 'Maria', 'Lee', 42, 'Jill', 'Jones', 28, 'Jack', 'Ford', 55]``

Finally, you can use the script below to get the total count:

`people_list = [    ["Jon", "Smith", 21],    ["Mark", "Brown", 38],    ["Maria", "Lee", 42],    ["Jill", "Jones", 28],    ["Jack", "Ford", 55],]flat_people_list = [i for x in people_list for i in x]number_of_elements = len(flat_people_list)print(number_of_elements)`

The result:

``15``