R/C2/Merging-and-Importing-Data/English

Title of script: Merging and Importing Data

Author: Shaik Sameer (IIIT Vadodara) and Sudhakar Kumar (IIT Bombay)

Keywords: R, RStudio, data merge, data import, video tutorial

Visual Cue	Narration
Show slide Opening slide	Welcome to the spoken tutorial on Merging and Importing Data
Show slide Learning Objectives	In this tutorial, we will learn how to: Use built-in functions for exploring a data frame Merge two data frames Import data in different formats in R
Show slide Pre-requisites http://spoken-tutorial.org	To understand this tutorial, you should know Data frames in R R script in RStudio How to set working directory in RStudio If not, please locate the relevant tutorials on R on this website.
Show slide System Specifications	This tutorial is recorded on Ubuntu Linux OS version 16.04 R version 3.4.4 RStudio version 1.1.456 Install R version 3.2.0 or higher.
Show slide Download files	For this tutorial, we will use, five data frames in different formats and a script file myDataSet.R. Please download these files from the Code files link of this tutorial.
[Computer screen] Highlight data frames and myDataSet.R in the folder myProject	I have downloaded these files from Code files link. And moved them to DataMerging folder in myProject folder on the Desktop. I have also set this folder as my Working Directory.
	Let us switch to RStudio.
Click myDataSet.R in RStudio Point to myDataSet.R in Rstudio	Open the script myDataSet.R in RStudio. For this, click on the script myDataSet.R. Script myDataSet.R opens in RStudio.
Highlight the Source button	Run this script by clicking on Source button.
Highlight captaincyOne in the Source window	captaincyOne appears in the Source window.
[RStudio] Highlight captaincyOne in the Source window	We will use some built-in functions of R to explore captaincyOne. For all the built-in functions used in this tutorial, please refer to the Additional Material.
	First, we will use summary function.
Highlight myDataSet.R in the Source window	Click on the script myDataSet.R
[RStudio] summary(captaincyOne) Highlight Source button	In the Source window, type summary and then captaincyOne in parentheses. Save the script and run the current line by pressing Ctrl+Enter keys simultaneously.
Highlight the output in the Console window	In the Console window, scroll up to locate the output. Statistical parameters for each column of captaincyOne are shown on the Console.
Highlight summary(captaincyOne) in the Source window	In the Source window, press Enter. Press Enter at the end of every command.
	Now, let us look at class function.
[RStudio] class(captaincyOne)	In the Source window, type class and then captaincyOne in parentheses. Save the script and run the current line.
Highlight the output in the Console window	class function returns the class of captaincyOne, which is data frame.
	Next let us look at typeof function.
[RStudio] typeof(captaincyOne)	In the Source window, type typeof and then captaincyOne in parentheses. Save the script and run the current line.
Highlight the output in the Console window	typeof function returns the storage type of captaincyOne, which is list.
Highlight typeof in the Source window	To know more about typeof function, we will access the help section of RStudio.
[RStudio] help(typeof)	In the Console window, type help, within parentheses typeof. Press Enter.
Highlight Description in the help window	typeof determines the R internal type or storage mode of any object.
Highlight Files tab in the lower right of RStudio	Click on the Files tab.
Highlight broom icon in the Console window	Clear the Console window by clicking on the broom icon.
Highlight captaincyOne in the Source window	Click on the data frame captaincyOne.
Highlight captaincyOne in Source window	Now, let us extract two rows from top of captaincyOne. For this, we will use head function.
Highlight myDataSet.R in the Source window	Click on the script myDataSet.R
[RStudio] head(captaincyOne, 2)	In the Source window, type head within parentheses captaincyOne comma space 2. Save the script and run the current line.
Highlight the output in the Console window	The top two rows of captaincyOne are shown on the Console window.
Highlight captaincyOne in the Source window	Click on the data frame captaincyOne.
Highlight CaptaincyOne in the Source window	Suppose we want to extract two rows from bottom of captaincyOne. For this, we will use the tail function.
Highlight myDataSet.R in the Source window	Click on the script myDataSet.R
[RStudio] tail(captaincyOne, 2)	In the Source window, type tail within parentheses captaincyOne comma space 2. Save the script and run the current line.
Highlight the output in the Console window	The last two rows of captaincyOne are shown on the Console window.
	Next, let us learn about str function. This function is used to display the structure of an R object.
[RStudio] str(captaincyOne)	In the Source window, type str within parentheses captaincyOne. Save the script and run the current line.
Highlight the output in the Console window	The structural details of captaincyOne are shown on the Console.
	Now, we will look at merging of data frames.
Show slide Merging data frames	Merging data frames has advantages like: It makes data more available. It helps in improving data quality. Combining similar data also reduces data complexity.
	Let us switch to RStudio.
[RStudio] Highlight CaptaincyData.csv and CaptaincyData2.csv under Files tab	We will learn how to merge two data frames CaptaincyData.csv and CaptaincyData2.csv.
[RStudio] captaincyTwo <- read.csv("CaptaincyData2.csv")	We will declare a variable captaincyTwo to store and read CaptaincyData2.csv. In the Source window, type the following command and press Enter.
[RStudio] View(captaincyTwo)	Now, type View within parentheses captaincyTwo. Save the script and run the last two lines.
Highlight captaincyTwo in Source window	The contents of captaincyTwo appear in the Source window.
Highlight the name of captains in captaincyTwo Highlight the column drawn in captaincyTwo	This data frame has the same captains as that in captaincyOne. However, it has different information about them like the number of matches drawn.
Highlight captaincyOne in the Source window	Now, we will update captaincyOne by adding information from captaincyTwo. For this, we use merge function.
Highlight myDataSet.R in the Source window	Click on the script myDataSet.R
	I am resizing the Source window.
[RStudio] captaincyOne <- merge(captaincyOne, captaincyTwo, by = "names")	In the Source window, type the following command. Press Enter.
Highlight by = "names" in the Source window	In the merge function, we use column names by which we want to merge two data frames. Here, it is names.
[RStudio] View(captaincyOne)	Now, type View and captaincyOne in parentheses. Save the script and run these two lines.
Highlight captaincyOne in the Source window	The contents of the updated captaincyOne appear in the Source window.
[RStudio] Highlight the tabs captaincyOne and captaincyTwo	Close the two tabs captaincyOne and captaincyTwo.
Cursor on the interface.	Now, we will learn how to import data of different formats in R.
[RStudio] # Importing data in different formats	We shall add one comment first. In the Source window, type # hash space Importing data in different formats.
Highlight CaptaincyData.xml under Files tab	Now, let us import CaptaincyData.xml file. For that, we need to install XML package. Make sure that you are connected to Internet.
	We need to install Ubuntu package libxml2-dev before installing XML package. Information on how to install this package, is provided in the Additional Material.
[RStudio] Click in the Console window	I have already installed libxml2-dev package. Hence, I will proceed for installing XML package now.
[RStudio] install.packages("XML") Highlight the red dot in the Console window	On the Console window, type install dot packages. Now, type XML inside double quotes and in parentheses. Press Enter. We will wait until R installs the package.
	Then, we load this package using library function.
Highlight myDataSet.R in the Source window	Click on the script myDataSet.R
Click at the top of the script myDataSet.R	Since we are loading a package, we will add it at the top of the script.
[RStudio] library(XML)	In the Source window, at the top of the script myDataSet.R, type library and XML in parentheses. Save the script and run this line.
[RStudio] Point to the comment. xmldata <- xmlToDataFrame("CaptaincyData.xml")	Now, in the Source window, click on the next line after the comment Importing data in different formats. Type the following command and press Enter.
[RStudio] View(xmldata )	Then type View and xmldata in parentheses. Save the script and run these two lines.
Highlight xmldata in the Source window	The contents of the xml file are shown here.
Highlight CaptaincyData.txt under Files tab	Next let us learn how to import CaptaincyData.txt.
Highlight myDataSet.R in the Source window	Click on the script myDataSet.R
[RStudio] txtdata <- read.table(“CaptaincyData.txt”)	In the Source window, type the following command and press Enter.
[RStudio] View(txtdata)	Next, type View and txtdata in parentheses. Save the script and run these two lines.
Highlight txtdata in the Source window	The contents of the text file are shown.
Highlight CaptaincyData.xlsx under the Files tab	Now, we will learn how to import data from the user interface of Rstudio. We will import the Excel file CaptaincyData.xlsx using this method. Please ensure that you have packages like readxl and Rcpp installed in your system.
Highlight Environment tab	In the top right corner of RStudio, click on the Environment tab.
Highlight Import Dataset button Highlight From Excel option	In the Environment tab, click on Import Dataset. From the drop-down menu, select From Excel.
Highlight Import Excel Data window	A window named Import Excel Data appears.
Highlight File/Url option	You can select a file on your computer or type the url from which you want to load an excel file. We will select a file on our computer.
Highlight Browse option	In the upper right corner of this window, near File/Url text field, click on Browse.
Highlight CaptaincyData.xlsx in the folder myProject	I will select the file CaptaincyData.xlsx located in DataMerging folder. This folder is in myProject folder on the Desktop. Click Open to load this file.
Highlight Data Preview option	Below the field File/Url, RStudio shows the preview of the Excel file being imported.
Highlight Code Preview option	At the bottom right corner of this window, you can see the code for importing this excel file.
Highlight Import button	Finally, click on the Import button.
Highlight CaptaincyData in the Source window	The contents of the Excel file are shown here.
	Let us summarize what we have learnt.
Show Slide Summary	In this tutorial, we have learnt how to: Use built-in functions for exploring a data frame Merge two data frames Import data in different formats in R
Show Slide Assignment	We now suggest an assignment. Using built-in dataset iris, implement all the functions we have learnt in this tutorial.
Show slide About the Spoken Tutorial Project	The video at the following link summarises the Spoken Tutorial project. Please download and watch it.
Show slide Spoken Tutorial Workshops	We conduct workshops using Spoken Tutorials and give certificates. Please contact us.
Show Slide Forum to answer questions	Pls post your timed queries in this forum.
Show Slide Forum to answer questions	Pls post your general queries in this forum.
Show Slide Textbook Companion	The FOSSEE team coordinates the TBC project. For more details, please visit these sites.
Show Slide Acknowledgement	The Spoken Tutorial project is funded by NMEICT, MHRD, Govt. of India
Show Slide Thank You	The script for this tutorial was contributed by Shaik Sameer (FOSSEE Fellow 2018). This is Sudhakar Kumar from IIT Bombay signing off. Thanks for watching.

Contributors and Content Editors

Madhurig, Nancyvarkey, Sudhakarst