View source for 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

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|'''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 '''opens 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
|| 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'''. 

We will learn more about '''list '''later in this series. 
|- 
|| 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 '''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’s 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. 

|- 
|| [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)'''
|| In the '''Source '''window, 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'''
|- 
|| [RStudio]

'''captaincyOne <- merge(captaincyOne, captaincyTwo, by = "names")'''
|| In the '''Source''' window, type the following command and 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&nbsp;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'''. 
|- 
|| this information can shown as a text while editing.

Pls mention this editing team.
|| 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.


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|| 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.
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