R/C2/Lists-and-its-Operations/English-timed

Time	Narration
00:01	Welcome to the spoken tutorial on Lists and its Operations.
00:06	In this tutorial, we will learn how to:
00:11	Create a list in R
00:14	Access the elements of a list
00:18	Perform indexing on lists
00:21	Combine two lists
00:25	To understand this tutorial, you should know,
00:28	Data frames in R'
00:31	Matrices and vectors in R
00:35	If not, please locate the relevant tutorials on R on this website.
00:42	This tutorial is recorded on
00:45	Ubuntu Linux OS version 16.04
00:51	R version 3.4.4
00:55	RStudio version 1.1.456
01:00	Install R version 3.2.0 or higher.
01:06	For this tutorial, we will use,
01:10	A data frame CaptaincyData.csv
01:15	and A script file myList.R.
01:20	Please download these files from the Code files link of this tutorial.
01:26	I have downloaded and moved these files to Lists folder.
01:32	This folder is located in myProject folder on my Desktop.
01:38	I have also set this folder as my Working Directory.
01:44	Let us switch to RStudio.
01:47	Open the script myList.R in RStudio.
01:53	I am resizing the Source window
01:58	Run this script by clicking on Source button.
02:02	captaincy data frame opens in the Source window.
02:07	Now let us create a matrix from a subset of captaincy.
02:13	We will convert the values in first three rows of played, won and lost columns into a matrix.
02:23	Click on the script myList.R
02:27	In the Source window, type the following commands.
02:31	Press Enter.
02:33	Press Enter at the end of every command.
02:37	Remember, as.matrix function is used to convert subData into a matrix.
02:45	Now let us create a numeric vector myVector.
02:51	In the Source window, type the following command.
02:54	Save the script and run the last three lines of code by pressing Ctrl + Enter keys simultaneously.
03:06	I am resizing the Source window
03:10	The three objects subData, matrixA and myVector are loaded in our workspace.
03:17	We will learn how to create a list in R by using the list function.
03:23	A list is an R object.
03:27	It has components of mixed data types like
03:33	strings
03:35	numbers
03:37	vectors
03:38	some other list inside it.
03:41	A list can also contain a matrix or a function as its elements.
03:48	A vector having all elements of the same type is called atomic vector,
03:56	whereas, A vector having elements of different types is called list.
04:02	Let us switch to RStudio.
04:05	We will create a list containing captaincy, matrixA and myVector.
04:13	I am resizing the Source window
04:18	In the Source window, type the following command.
04:21	Now, we will assign names to the elements of myList.
04:27	For this, we will use names function.
04:31	In the Source window, type the following command.
04:35	We will assign the following names,
04:40	dataframe to captaincy.
04:44	matrix to matrixA
04:47	vector to myVector
04:49	In the Source window, now type print, myList in parentheses.
04:55	Run the last three lines of code.
04:59	I am resizing the Console window.
05:03	In the Console window, three elements of myList are shown with their respective names.
05:11	Hence, myList is a named list.
05:15	Now, we will learn how to access the elements of a list.
05:21	I am resizing the Console window.
05:25	Elements of the list can be accessed by the index of the elements in the list.
05:32	It is also known as indexing.
05:35	In case of named lists, it can also be accessed by using the names.
05:43	Suppose we want to access the element named as dataframe of myList.
05:49	In the Source window, type myList dollar sign dataframe
05:56	Run the current line.
05:58	captaincy dataframe, which is an element of myList, is shown on the Console.
06:04	We can also access an element by using its index.
06:11	Suppose we want to access the element named matrix of myList.
06:17	Index of matrix is 2 in myList.
06:21	In the Source window, type myList and 2 in square brackets.
06:28	Run the current line.
06:31	matrix element of myList is shown on the Console.
06:36	Now, suppose we want to access the third column of matrix element of myList.
06:42	For this, we use double square brackets.
06:47	In the Source window, type the following command.
06:51	2 in double square brackets denotes that second element of myList is to be accessed.
07:00	comma 3 in single square brackets denotes that third column of second element is to be accessed.
07:08	Remember we use single square bracket notation with two indices for indexing a data frame.
07:17	First index and second index refer to row and column respectively.
07:23	Also, leaving an index blank indicates that we want to keep all the elements in that dimension.
07:31	Run the current line.
07:34	The elements of third column of matrix element are displayed on the Console.
07:40	Now, let us learn how to combine two different lists.
07:45	First, we will create a simple list.
07:49	In the Source window, type the following command.
07:53	Save the script and run the current line.
07:57	Now, we declare an object named merged dot list.
08:03	It is used for storing the combined output of myList and listSimple.
08:11	In the Source window, type the following commands.
08:15	Save the script and run the last three lines of code.
08:20	I am maximizing the Console window.
08:24	Now, scroll up to locate the output.
08:28	The combined list is shown on the Console.
08:33	Let us summarize what we have learnt.
08:37	In this tutorial, we have learned how to
08:41	Create a list in R
08:43	Access the elements of a list
08:46	Perform indexing on lists
08:50	Combine two lists
08:53	We now suggest an assignment.
08:56	Create a numeric vector c(1:5) and a 5 by 3 matrix with elements from 1 to 15.
09:04	Create a named list with vector, matrix and iris data set.
09:11	Retrieve the iris data set from the list using dollar operator and indexing method.
09:18	State the differences between the results obtained by using dollar operator and indexing method of accessing iris.
09:28	For solutions, please refer to the Additional Material section on this website.
09:35	The video at the following link summarises the Spoken Tutorial project.
09:41	Please download and watch it.
09:44	We conduct workshops using Spoken Tutorials and give certificates.
09:49	Please contact us.
09:52	Please post your timed queries in this forum.
09:57	Please post your general queries in this forum.
10:01	The FOSSEE team coordinates the TBC project.
10:05	For more details, please visit these sites.
10:08	The Spoken Tutorial project is funded by NMEICT, MHRD, Govt. of India
10:15	The script for this tutorial was contributed by Shaik Sameer (FOSSEE Fellow 2018).
10:22	This is Sudhakar Kumar from IIT Bombay signing off. Thanks for watching.

Contributors and Content Editors

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