How to Get the Number of Elements in a Python List?In this article, we will discuss how to get the number of elements in a Python List. Show
Examples:
Before getting the Number of Elements in the Python List we have to create an empty List. After creating an empty list we have to insert the items or elements into the list. There are two methods to get the number of elements in the list i.e,
Using Len() functionWe can use the len function i.e len( ) to return the number of elements present in the list Python3
Output
[1, 2, 3, 4]
No of elements in list are
4
Using for loopWe can declare a counter variable to count the number of elements in the list using a for loop and print the counter after the loop gets terminated. Python3
Output
[1, 2, 3, 4]
No of elements in the list are
4
Hence, in this way, we can return the number of elements of a list in python using for loop. Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics. To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course. And to begin with your Machine Learning Journey, join the Machine Learning - Basic Level Course
Article Tags :
Python Python Programs
Python list-programs Python List count()In this tutorial, we will learn about the Python List count() method with the help of examples. The count() method returns the number of times the specified element appears in the list. Example# create a list numbers = [2, 3, 5, 2, 11, 2, 7]# check the count of 2
count = numbers.count(2)
print('Count of 2:', count)
# Output: Count of 2: 3ExplanationEverything in Python is an object, including lists. All objects have a header of some sort in the C implementation. Lists and other similar builtin objects with a "size" in Python, in particular, have an attribute called ob_size, where the number of elements in the object is cached. So checking the number of objects in a list is very fast. But if you're checking if list size is zero or not, don't use len - instead, put the list in a boolean context - it treated as False if empty, True otherwise. len(s)
len is implemented with __len__, from the data model docs: object.__len__(self)
And we can also see that __len__ is a method of lists: items.__len__()returns 3. Get the number of items of a list in PythonPosted: 2021-09-11 / Tags: Python, List Tweet In Python, the built-in function len() is used to get the length (the number of items) of a list.
This article describes the following contents.
See the following article for the usage of len() for objects of other types.
You can get the total number of elements with len(). If you want to get the number of occurrences of an element, use the count() method or Counter of the standard library collections.
Sponsored Link List in PythonA list in Python is implemented to store the sequence of various types of data. However, there are six data types in Python that are capable of storing the sequences but the most common and reliable type is a list. To learn more about python you can join our Master Python programming course. A list is defined as a collection of values or items of different types. The items in the list are separated with a comma (,) and enclosed with the square brackets []. It is defined as follows: list1 = ['edureka', 'python', 2019]; list2 = [1, 2, 3, 4, 5 ]; list3 = ["a", "b", "c", "d"];If you want to learn Artificial Intelligence and Machine Learning in-depth, come to us and sign up for this Post Graduate Diploma AI and ML courses. Python List len() MethodAdvertisements Previous Page Next Page Python List Count With ExamplesPython Lists can contain objects of the same type or of different types. For example, a List can contain all items as Integer or items as integer, String, boolean etc. The length of the list can be identified using the len() and using for loop. Using Len() FunctionIn Python, you can find the length of the list using the len() function. Use the below snippet to get the count of elements in list. Snippet list = ['a','b','c'] len(list)There are 3 elements in the list. You’ll see the output as 3. Output 3You’ve calculated the items in the list which have the same type of values. Next, you’ll see the list with different types of items. Count List with Different Type of Items The example list contains one character, one number, one boolean value, and one value None which is used to denote the missing data. However, when a list has None, it is also counted as one element while using len() function. Snippet list = ['a',1, True, None] len(list)The example list has 4 values including None. Hence, you’ll see the output 4. Output 4This is how you can get the number of elements in the list using the len() function. This is also known as finding list length. Next, you’ll learn how to use for loop. Using For LoopIn this section, you’ll learn how to count the number of elements in a list using the for loop. for loop is used to iterate over a sequence of values. To get the number of elements in the list, you’ll iterate over the list and increment the counter variable during each iteration. Once the iteration is over, you’ll return the count variable which has the total number of elements in the list. In the below example,
Snippet list = ['a',1, True, None] def get_no_of_elements(list): count = 0 for element in list: count += 1 return count print("Number of elements in the list: ", get_no_of_elements(list))There are 4 elements in the list including the None value. Hence you’ll see output 4. Output Number of elements in the list: 4This is how you can get the number of elements in a list using for loop. Next, let us discuss the counting with condition. Count elements in a flat listSuppose we have a list i.e. To count the elements in this list, we have different ways. Let’s explore them, Use len() function to get the size of a listPython provides a inbuilt function to get the size of a sequence i.e. Arguments:
It returns the length of object i.e. count of elements in the object. Advertisements Now let’s use this len() function to get the size of a list i.e. Output: Number of elements in list : 9 How does len() function works ? When len(s) function is called, it internally calls the __len__() function of the passed object s. Default sequential containers like list, tuple & string has implementation of __len__() function, that returns the count of elements in that sequence. So, in our case we passed the list object to the len() function. Which internally called the __len__() of the list object, to fetch the count of elements in list. Use list.__len__() to count elements in a listWe can directly call the __len__() member function of list to get the size of list i.e. Output: Number of elements in list : 9 Although we got the size of list using __len__() function. It is not a recommended way, we should always prefer len() to get the size of list. |