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Python Program To Find Length Of A List

The length of a list is equal to the number of elements present in it.

In this article, we will discuss different ways in which we can find out the length of a list in Python.

Find the length of a List using the Naive method in Python

This is the most basic approach to finding the length of a list. Here, we maintain a counter variable and initialize it 0.

We then count the number of elements in the list using a for loop. In each iteration, we increment the value of the counter variable by 1. When the loop terminates the counter variable stores the length of the list.

Let's look at the algorithm of this approach to understand better.

Algorithm to find the length of the list in Python

  1. Initialize a list je_list

  2. Declare a counter variable je_counter and initialize it to 0

  3. Start for-each loop to je_list and increment je_counter variable by 1

  4. Display length using je_counter

Python Code

# Initialise a list
je_list = [ 1, 3, 43, 66, 321, 4 ]
​
# declare and initialize a counter variable
je_counter = 0
​
# apply a for each loop
for je_ele in je_list:
    je_counter = je_counter +1
​
# display je_counter
print(je_counter)

Output:

6

Find the length of a List using len() method in Python

Python has an in-built method called the len() method. This method takes an iterable object as its argument and returns the length of that iterable object.

It is the most convenient and commonly used approach. Look at the code below:

# Initialise a list
je_list = [ 1, 3, 43, 66, 321, 4 ]
​
# using length function
je_len = len(je_list)
​
# print length
print(je_len)

Output:

6

Find the length of a List using the length_hint() method in Python

This method is exactly like the len() method except that declared in the operator class. So, we must import the operator class before using this method. It returns the number of elements present in a list. Look at the code below.

from operator import length_hint
# Initialise a list
je_list = [ 1, 3, 43, 66, 321, 4 ]
​
# using length_hint function
je_len = length_hint(je_list)
​
# print length
print(je_len)

Output:

6