How to Find the Length of a List in Python

May 27, 2025 / Tutorial

In Python, a list is a way to store multiple items in a single variable. For example, you might have a list of numbers, names, or even a mix of different types of data. Sometimes, you need to know how many items are in a list. This is called the length of the list.

Python makes it very easy to find the length using a built-in function called len(). Let’s go through this step by step.

Step 1: What is a List?

A list is a collection of items written inside square brackets []. Items are separated by commas.

numbers = [5, 10, 15, 20]

This list has 4 items: 5, 10, 15, and 20.

Step 2: Why Do We Need the Length of a List?

Knowing the length of a list is useful when:

  • You want to loop through all items.
  • You want to check if the list is empty.
  • You want to divide the list into parts.
  • You want to display the number of items to the user.

Step 3: Using the len() Function

Python provides a simple function called len() to count the number of items in a list.

Syntax:

len(list_name)
Example:
numbers = [5, 10, 15, 20]
print(len(numbers))
Output:
4
This means the list has 4 items.

Step 4: Storing the Length in a Variable

You can also store the result of len() in a variable if you want to use it later in your program.

Example:
fruits = [“apple”, “banana”, “cherry”]
count = len(fruits)
print(“There are”, count, “fruits in the list.”)

Output:
There are 3 fruits in the list.

Step 5: len() Works with Other Data Types Too

The len() Function is not just for lists. It also works with:

  • Strings – counts the number of characters
  • Tuples – count the number of items
  • Dictionaries – count the number of key-value pairs

Example:
len(“hello”) # Output: 5
len((1, 2, 3)) # Output: 3
len({“a”: 1, “b”: 2}) # Output: 2

Conclusion

This article introduced various methods to determine the length of a list in Python.

Find more information about how to check Python Version in Linux & Windows

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