How to find the length of a list in Python

Introduction

There are several techniques you can use in Python to find the length of a list. The length of a list is the number of elements in the list. To get the length of a list in Python, the most common way to do this is to use the len() method, which is the most efficient and a built-in function. Since a list is an object, the size of the list if already stored in memory for quick retrieval.

We have also included two other methods that you can use to find the length of a list with Python.

Using the method len() To get the length of a list

To find the length of a list, you can use the built-in len() method. The len() method takes a sequence or set as an argument and returns the number of elements in the sequence or set.

The syntax of len() is as follows:

len(s)

The following example provides a list and uses the method len() To get the length of the list it uses:

inp_lst = ['Python', 'Java', 'Ruby', 'JavaScript']
size = len(inp_lst)
print(size)

The output is:

Output
4

Alternative ways to find the length of a list

Although the method len() It is usually the best way to get the length of a list because it is the most efficient method, there are a few other ways to find the length of a list in Python.

Using the method length_hint() To get the length of a list

The Python operator module has one method. length_hint() To estimate the length of a given iterable object. If the length is known, the method length_hint() Returns the actual length. Otherwise, the method length_hint() Returns the estimated length. For lists, the length is always known, so you usually just use the method len() You use.

Syntax length_hint() It is as follows:

length_hint(object)

The following example provides a list and uses the method length_hint() To get the length of the list it uses:

from operator import length_hint 
inp_lst = ['Python', 'Java', 'Ruby', 'JavaScript']
size = length_hint(inp_lst)
print(size)

The output is:

Output
4

Using a for loop to get the length of a list

This section provides a less practical, but still informative, way to find the length of a list without any specific method. Using python for loop to get the length of a list is also known as a simple and straightforward method and can be used in almost any programming language.

The basic steps to get the length of a list using a for loop are:

• Declare a counter variable and set it to zero.

counter = 0

• Use a for loop to loop through all the data elements and increment the counter variable by 1 after encountering each element.

for item in list:
counter += 1

• The length of the array is stored in the counter variable and the variable represents the number of elements in the list. The variable can be used in other code or output.

print(counter)

The following example shows how to get the length of a list:

inp_lst = ['Python', 'Java', 'Ruby', 'JavaScript']
size = 0
for x in inp_lst:
size += 1
print(size)

The output is:

Output
4

Result

In this article, you learned different ways to find the length of a list in Python. Continue your learning with more Python tutorials.