Last index list python

Lists are one of the most commonly used data structures in python programs. In this article, we will look at different ways to get the last element of a list in python. For this, we will use ways like indexing, pop[] method, slicing and reverse iterator.

Get the last element of a list using indexing in Python

Indexing in python is a way to access elements from a list. In python, we can use positive indices as well as negative indices. Positive indices start with zero which corresponds to the first element of the list and the last element of the list is identified by the index listLen-1 where listLen is the length of the list.

Alternatively, negative indices start from -1 which corresponds to the last element of the list. It goes till -listLen where listLen is the length of the list. The index -listLen corresponds to the first element in the list.

To get the last element of a list, we can first find the length of the list using the len[] function. Then we can access the last element of the list at the index listLen-1 as follows.

myList = [1, 2, 3, 4, 5, 6, 7] print["Given List is:", myList] listLen = len[myList] lastElement = myList[listLen - 1] print["Last element of the list is:", lastElement]

Output:

Given List is: [1, 2, 3, 4, 5, 6, 7] Last element of the list is: 7

Alternatively, we can use negative indexing to access the last element of the list. The last element of the list is at index -1 which can be accessed as follows.

myList = [1, 2, 3, 4, 5, 6, 7] print["Given List is:", myList] lastElement = myList[- 1] print["Last element of the list is:", lastElement]

Output:

Given List is: [1, 2, 3, 4, 5, 6, 7] Last element of the list is: 7

We can see that while using negative indexing, we dont have to calculate the length of the list.

Using the pop[] method

The pop[] method is used to remove any element from the list from a specified index. It takes the index of the element as an optional input parameter and returns the element at the specified index after deleting it from the list. If no input parameter is passed, it will return the last element of the list after deleting it.

We can use the pop[] method to get the last element of the list as follows.

myList = [1, 2, 3, 4, 5, 6, 7] print["Given List is:", myList] lastElement = myList.pop[] print["Last element of the list is:", lastElement]

Output:

Given List is: [1, 2, 3, 4, 5, 6, 7] Last element of the list is: 7

Remember that the pop[] method also deletes the element which is accessed. So, Use this method only when you also want to delete the last element of the list.

Get the last element of a list using Slicing in Python

In python, slicing is an operation to create a subpart of a string or a list. With slicing, we can access different parts of any string, tuple or a list. To perform slicing on a list named, we use the syntax listName[start, end,interval] where start and end are the indices at which the sliced list starts and ends in the original list respectively. The interval is used to select elements in a sequence. The elements are selected from the list at the indices which are whole number multiples of interval away from the start index.

To access the last element of a list using slicing in python, we can slice a list in such a way that it contains only the last element. Then we can access that element as follows.

myList = [1, 2, 3, 4, 5, 6, 7] print["Given List is:", myList] lastElement = myList[-1:][0] print["Last element of the list is:", lastElement]

Output:

Given List is: [1, 2, 3, 4, 5, 6, 7] Last element of the list is: 7

Get the last element of a list using reverse iterator

We can use a reverse iterator to get the last element of the list. To create a reverse iterator, we can use the reversed[] method. The reversed[] method takes any iterable object as input and returns a reverse iterator of the iterable.

To get the last element of a list, we will first create a reverse iterator of the list using the reversed[] method. Then we will access the first element of the reverse iterator which will be the last element of the original list. This can be done as follows.

myList = [1, 2, 3, 4, 5, 6, 7] print["Given List is:", myList] reverseIter = reversed[myList] lastElement = next[reverseIter] print["Last element of the list is:", lastElement]

Output:

Given List is: [1, 2, 3, 4, 5, 6, 7] Last element of the list is: 7

Get the last element of a list using itemgetter

We can create an itemgetter object to access the last element of a list. The itemgetter[] method is defined in the operator module in python. The itemgetter[] method takes the index as input which creates a callable object. The callable object takes an iterable as input and extracts the element at the specified index.

To access the last element of the list, we can call itemgetter[] method with input index as -1 and then we can access the last element of the list as follows.

import operator myList = [1, 2, 3, 4, 5, 6, 7] print["Given List is:", myList] lastElement = operator.itemgetter[-1][myList] print["Last element of the list is:", lastElement]

Output:

Given List is: [1, 2, 3, 4, 5, 6, 7] Last element of the list is: 7

Conclusion

In this article, we have seen different ways to get the last element of a list in python. To read more about lists, read this article on list comprehension in python. Stay tuned for more informative articles.