Book Image

R Data Structures and Algorithms

By : PKS Prakash, Achyutuni Sri Krishna Rao
Book Image

R Data Structures and Algorithms

By: PKS Prakash, Achyutuni Sri Krishna Rao

Overview of this book

In this book, we cover not only classical data structures, but also functional data structures. We begin by answering the fundamental question: why data structures? We then move on to cover the relationship between data structures and algorithms, followed by an analysis and evaluation of algorithms. We introduce the fundamentals of data structures, such as lists, stacks, queues, and dictionaries, using real-world examples. We also cover topics such as indexing, sorting, and searching in depth. Later on, you will be exposed to advanced topics such as graph data structures, dynamic programming, and randomized algorithms. You will come to appreciate the intricacies of high performance and scalable programming using R. We also cover special R data structures such as vectors, data frames, and atomic vectors. With this easy-to-read book, you will be able to understand the power of linked lists, double linked lists, and circular linked lists. We will also explore the application of binary search and will go in depth into sorting algorithms such as bubble sort, selection sort, insertion sort, and merge sort.
Table of Contents (17 chapters)
R Data Structures and Algorithms
Credits
About the Authors
Acknowledgments
About the Reviewer
www.PacktPub.com
Preface

Array-based list


The array-based list, also known as array list, is a resizable array implementation. Thus, as more elements are added to the linked list, its size increases dynamically. The array-based list assigns an element to the assigned array; however, if a new element is assigned some data, and there is no space in the array, then it allocates a new array, and moves all the data to the newly allocated array. For example, as shown in Figure 3.19, since the array is full, all of the data is reassigned to a bigger array by increasing the size by a default value.

Figure 3.19: Example array-based link list

Let us set up a reference class ALinkList for an array list in R. To set up an array linked list, the class fields required are as follows:

  • Alist: To store the dataset

  • listsize: Pointer to the current location in the array; this can also be used to get the current list size

  • arraysize: Default expansion size

  • maxSize: Maximum array size

The defined class initializes an arraysize of 100...