Performance Analysis: Naive vs Python len() vs Python length_hint()
When choosing amongst alternatives it’s always necessary to have a valid reason why to choose one over another. This section does a time analysis of how much time it takes to execute all of them to offer a better choice to use.
Python3
from operator import length_hintimport time# Initializing listtest_list = [1, 4, 5, 7, 8]# Printing test_listprint("The list is : " + str(test_list))# Finding length of list# using loop# Initializing counterstart_time_naive = time.time()counter = 0for i in test_list: # incrementing counter counter = counter + 1end_time_naive = str(time.time() - start_time_naive)# Finding length of list# using len()start_time_len = time.time()list_len = len(test_list)end_time_len = str(time.time() - start_time_len)# Finding length of list# using length_hint()start_time_hint = time.time()list_len_hint = length_hint(test_list)end_time_hint = str(time.time() - start_time_hint)# Printing Times of eachprint("Time taken using naive method is : " + end_time_naive)print("Time taken using len() is : " + end_time_len)print("Time taken using length_hint() is : " + end_time_hint) |
Output:
The list is : [1, 4, 5, 7, 8]
Time taken using naive method is : 2.6226043701171875e-06
Time taken using len() is : 1.1920928955078125e-06
Time taken using length_hint() is : 1.430511474609375e-06
In the below images, it can be clearly seen that time taken is naive >> length_hint() > len(), but the time taken depends highly on the OS and several of its parameter.
In two consecutive runs, you may get contrasting results, in fact sometimes naive takes the least time out of three. All the possible 6 permutations are possible.
naive > len() > length_hint()
naive > len()=length_hint()
naive > length_hint() >len()
naive > length_hint() > len()
We have discussed 8 different methods to find the length of a list in Python. We have also done a performance analysis to check which method is the best.
You can use any of the above methods to find the length of a list. Finding list length is very useful when dealing with huge lists and you want to check the number of entries.
Check Out More Python Lists Pages:
How To Find the Length of a List in Python
List being an integral part of Python programming has to be learned by all Python users and having a knowledge of its utility and operations is essential and always a plus.
Many operations are performed in lists, but in this article, we will discuss the length of a list. The length of a list means the number of elements it has. We are going to look at 8 different methods to find the length of a list in Python.
Example:
Input: lst = [10,20,30,40]
Output: 4
Explanation: The output is 4 because the length of the list is 4.
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