How to get the size of a list in Python?

In Python, a list is an ordered sequence that can hold several object types, such as integers, characters, or floats. In other programming languages, a list is equivalent to an array.

In this article, we need to determine the size of a list, which refers to its length. For instance, the list [10, 20, 30, 40] has a length of 4.

Using 'len()' method

In Python, the len() method returns the number of items in a list.

Example

In the following example, we have created an input list and to find the length of the list, it is passed an argument to the len() method -

my_list = ['Hello', 12,'Tutorialspoint', 3, 24, 9]
print("Given list-",my_list)
my_len=len(my_list)
print("Length of the given list -",my_len)

Following is the output of the above code -

Given list- ['Hello', 12, 'Tutorialspoint', 3, 24, 9]
Length of the given list - 6

Using a for loop

We can also find the length of the list by iterating through it using a for loop.

Example

Here, we have initialised the count variable to zero and iterated through the list and incremented each time by 1 -

count=0
my_list = ['Hello', 12,'Tutorialspoint', 3, 24, 9]
print("Given list-",my_list)
for i in my_list:
   count=count+1

print("Length of the list-",count)

Following is the output of the above code -

Given list- ['Hello', 12, 'Tutorialspoint', 3, 24, 9]
Length of the list- 6

Using __len__() Function

The __len__() function in Python returns a positive integer representing the length of the object on which it is called. It implements the in-built len() function.

Example

The following program returns the size of the list using the __len__() function -

# input list
my_list = ['Hello', 12,'Tutorialspoint', 3, 24, 9]

# getting list length using the __len__() function
my_len = my_list.__len__()

# Printing the size of a list
print("Size of a List = ", my_len)

Following is the output of the above code -

Size of a List =  6