Data import and export
Lukáš Lehotský and Petr Ocelík
Summary of the last lesson
• Logical conditions or index positions allow for object filtering, when inserted into square brackets
• Square brackets must include all object dimensions
• When filtering data frames, filtering condition usually applies to rows
condition <- df[  ,3]  > 1000000
df[ condition , ]
cars    type price consumption
1 BMW     3 1200000 6.2
2 Audi    A4        1164000 5.9
df.sub <- df[ condition , ]
Working directory
• Folder, where all imports and exports are taking place
• Makes data import and export easier
• Functions setwd () and getwd ()
getwd()
[1]   "C:/Users/Lukas/. . .
setwd("C:\\Users\\Lukas\\Documents\\R intro") setwd("C:/Users/Lukas/Documents/R intro")
Working directory
• There are few issues/limitations
• R does not accept single backslash \ in Win path
• Typically, this is path copied from the Win explorer
• It's necessary to replace backslash \ with forwardslash / or double backslash \\
• Sometimes, there's an issue with non-standard letters in the path
• Typically, in user-name paths in Win
• Solution is to move R and working directory out
File  Edit   Code  View Plots
0] Untrtledl
I £3 I H □ Source
Session   Build   Debug  Erofile  lools Help
New Session
Interrupt R lerminate R...
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Ctrl+Shift+F10
Set Working Directory
Load Workspace... Save Workspace As..,
Clear Workspace,,,
Quit Session...
_+Run _   Source -
,   I      Environment History
|   £jf Q    J* Import Dataset - I Global Environment
^ Project: (None) ■
To Source File Location To Files Pane Location
Choose Directory.,,
Ctrl+Shift+H
Ctrl+Q
1:1       (Top Level) t
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> I
R Script : can
Files	Plots    Packages    Help Viewer			= n
Ol Install    © Update		1 (<*		MC9I
	Name	Description	Version	I I
User Library				A
□	abind	Combine Multidimensional Arrays	1.4-5	
□	acepack	ACE and AVAS for Selecting Multiple Regression Transformations	1,4,1	©
□	assertthat	Easy Pre and Post Assertions	0.2.0	©
□	audio	Audio Interface for R	0.1-5	©
□	backports	Reimplementations of Functions Introduced Since R-3.0.0	1.1.0	©
□	base64enc	Tools for base64 encoding	0.1-3	©
□	beepr	Easily Play Notification Sounds on any Platform	1.2	©
□	BH	Boost C + + Header Files	1.62.0-1	
□	bindr	Parametrized Active Bindings	0.1	©
□	bindrcpp	An 'Repp' Interface to Active Bindings	0.2	
□	bltcps	Bitwise Operations	1.0-6	©
□	Cairo	R graphics device using cairo graphics library for creating high-quality bitmap (PNG, JPEG, TIFF], vector (PDF, SVG, PostScript) and display (X11 and Win32) output	1.5-9	©
Data import
• R Studio visual import
• Functions
• Structured data (tables)
• Unstructured data
• R native files
o	RStudio		- °D
File   Edit   Code  View  Plots  Session   Build   Debug   Profile  Tools Help			
CH Ä*l Q 01 Qli^Goto file/function          1 @ -    Addins »			^  Project: (None) »
			
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Home ■»		
CR R Resources U	I RStudio	A
Learning R Online CRAN Task Views R on StackOverflow Getting Help with R
Manuals
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R Data Import/Export
Reference
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Packages
Search Engine & Keywords
Data import: structured data
• Most common format of tabular data
• CSV-comma-separated value
• TSV-tab-separated value
• TXT - plain text file
• Other formats (XLSX,...)
• CSV/TSV are most desired
• Essentially, CSV and TSV files are text files
PSPad - [C:\Users\Lukas\Downloads\BALIBOMBING2002_2002.csv]
[7? File  Projects  Edit Search	View  Format Tools HTML				Settings	Window Help(x)								1- II B	X
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1.. BALIB0MBING2ÜÜ2_2ÜÜ2.csv o              ie 20	3&	40			50	60	79		90		100			ne 120	
1529,1594
L
151,0,2,2,2,2,2,2,2,2,2,2,2,2,0,0,0,0,0,0,0,0,0,0,9,0,0,0 153,2,0,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,0,0,0,0,0,0,0,0,9,0 155,2,2,0,2,3,3,2,2,2,2,2,0,2,2,0,2,2,2,2,2,2,0,0,0,0,9,0 160,2,2,2,0,2,2,2,2,2,2,2,0,2,2,2,2,2,2,2,1,2,2,2,2,2,2,2 162,2,2,3,2,0,3,2,2,2,2,0,0,2,2,2,2,2,0,0,2,2,0,0,0,0,0,0 163,2,2,3,2,3,0,2,2,2,2,0,0,2,2,2,2,2,2,2,2,2,2,0,0,0,9,0 175,2,2,2,2,2,2,0,2,2,2,0,0,2,2,1,2,1,0,0,2,2,0,0,0,0,9,0 177,2,2,2,2,2,2,2,0,2,2,2,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0 180,2,2,2,2,2,2,2,2,0,2,2,9,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0 183,2,2,2,2,2,2,2,2,2,0,0,0,2,2,2,2,2,0,2,2,2,0,0,0,0,0,0
189,2,2,2,2,0,0,0,2,2,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0 650, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 , 0 , 0, Ö, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
1579,2,2,2,2,2,2,2,2,2,2,2,0,0,2,0,2,2,0,0,0,2,0,0,0,0,0,0
176,0,2,2,2,2,2,2,0,0,2,0,0,2,0,2,2,2,0,0,2,2,0,0,0,0,0,0
1549,0,2,0,2,2,2,1,0,0,2,0,0,0,2,0,2,2,0,0,0,2,0,0,0,0,0,0
1564,0,2,2,2,2,2,2,0,0,2,0,0,2,2,2,0,2,0,0,2,2,0,0,0,0,0,0
1576,0,2,2,2,2,2,1,0,0,2,0,0,2,2,2,2,0,0,0,0,2,0,0,0,0,0,0
524,0,0,2,2,0,2,0,0,0,0,0,0,0,0,0,0,0,0,2,0,2,0,2,2,2,2,2
588,0,0,2,2,0,2,0,0,0,2,0,0,0,0,0,0,0,2,0,0,2,0,0,0,0,0,0
1532,0,0,2,2,2,2,2,0,0,2,0,0,0,2,0,2,0,0,0,0,2,0,0,0,0,0,0
1597,0,0,2,2,2,2,2,0,0,2,0,0,2,2,2,2,2,2,2,2,0,0,2,2,2,0,2
590,0,0,0,2,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
1503,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,2,0,0,2,0,0,2,2,2,2
1512,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,2,0,0,2,0,2,0,2,2,2
1513,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,2,0,0,2,0,2,2,0,2,2
1529,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,2,0,0,0,0,2,2,2,0,2
1594,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,2,0,0,2,0,2,2,2,2,0
1 : 47 / 29 [1727]
, 44 $Q02C
Text
DOS   Code page: UTF-8
Data import: structured data
	151	153	155	160	162
151	0	2	2	2	2
153	2	0	2	2	2
155	2	2	0	2	3
160	2	2	2	0	2
Data import: structured data
• BAUBOMBING2002_2002.csv
• Matrix
• Stored as a comma-separated value
• First row - column names (note first cell is empty)
• First column - row names
• No missing values/texts
Data import: structured data
• Most common function read. table ()
• Import any structured (tabular) data
• Highly customizable - many arguments
• Always imports data as data frame
df <- read.table(  file = "BALIBOMBING2002_2002.csv",
header = TRUE, sep = 11, 11 , row.names = 1, na.strings = "NA", stringsAsFactors = FALSE, fileEncoding = "UTF-8")
File   Edit   Code  View   Plots   Session   Build   Debug   Profile   lools | Help
df												>□	
	- i a I	" Filter											
	XI51	XI53	X155	X160	XI82	XI63	X175	X177	X180	X1S3	X1S9	X650	
151	0	2	2	2	2	2	2	2	_2_	2	2		A
153	2	0	2	2	2	2	2	2	2	2	2		
155	2	2	0	2	3	3	2	2	2	2	2		
160	2	2	2	0	2	2	2	2	2	2	2		
162	2	2	3	2	0	3	2	2	2	2	0		
163	2	2	3	2	3	0	2	2	2	2	0		1
175	2	2	2	2	2	2	0	2	2	2	0		
177	2	2	2	2	2	2	2	0	2	2	2		
180	2	2	2	2	2	2	2	2	0	2	2		
133	2	2	2	2	2	2	2	2	2	0	0		
189	2	2	2	2	0	0	0	2	2	0	0		
850	2	2	0	0	0	0	0	0	0	0	0		
1579	2	2	2	2	2	2	2	2	2	2	2		V
													
< |												>	
Showing 1 to 15 of 27 entries													
Environment    History Connections
\3* Id    FH* Import Dataset -Global Environment -
Data df
List -
27 obs. of 27 variables
Console Terminal	
C:/Users/Lukas/Downloads/	
> df <- read.table(	file = "BALIBOMBING2002_2ee2.csv",
+	header = TRUE,
+	_ _       _    ii ir sep =    , ,
+	row-names = ls
+	na.strings = "NA",
+	stringsAsFactors = FALSE,
+	fileEncoding = "UTF-8")
>	
Files	Plots Packages	Help Viewer		= r
6| install    (f) Update				i <§>
	Mame	Description	Version	
User Library				A
□	abind	Combine Multidimensional Arrays	1.4-5	
□	acepack	ACE and AVAS for Selecting Multiple Regression Transformations	1.4.1	0
□	antiword	Extract Text from Microsoft Word Documents	1.1	0
	assertthat	Easy Pre and Post Assertions	0.2.0	
□	audio	Audio Interface for R	0.1-5	0
□	backports	Reimplementation5 of Functions Introduced Since R-3.0.0	1.1.2	&
	base64enc	Tools for baseS4 encoding	0.1-3	0
□	beepr	Easily Play Notification Sounds on any Platform	1.2	w
□	BH	Boost C++ Header Files	1.66.0-1	0
□	bindr	Parametrized Active Bindings	0.1.1	0
□	bind repp	An 'Repp' Interface to Active Bindings	0.2.2	_0
□	bit	A Class for Vectors of 1-Bit Booleans	1.1-13	A
□	bit64	A S3 Class for Vectors of 64bit Integers	0.9-7	0
□	bitops	Bitwise Operations	1.0-6	0
□	blob	A Simple S3 Class for Representing Vectors of Binary Data (BLOBS')	1.1.1	0
□	brew	Templating Framework for Report Generation	1.0-6	
□	ca	Simple, Multiple and Joint Correspondence Analysis	0.70	
Data import: unstructured data
• Most common to use function readLines ()
• Can import any unstructured data as a character vector
• Data conversions/mining must follow
text <- readLines(con = "BALIBOMBING2002_2002.csv",
warn = TRUE, encoding = "UTF-8")
Data import: RData files
• R has native data format
• Allows to save whole environment (all objects) or particular object for later use
• Easiest way to access/share previous R work
• Function load ()
load(file = "balibombing.rdata")
RStudio
File   Edit   Code  View   Plots   Session   Build   Debug   Profile  Tools Help
Q   ' t3? " i_i Go to file/function I BS " Addins
£■1 Project: [None] -
df
Filter
Showing 1 to 15 of 27 entries
Console Terminal
C:/Users/Lukas/Downloads/ >
> str(df)
'data.frame'
$ X151 $ X153 $ X155
$ xiee
$ X162 $ X163 $ X175 $ X177
$ xise
$ X1S3 $ X1S9
int int int int int int int int int int int
27
e 2
2 0
2 2
2 2
2 2
2 2
2 2
2 2
2 2
2 2
2 2
obs. of   27 variables:
e e
	X151	XI53	XI55	XI60	XI62	XI63	XI75	XI77	X1S0	X13J	X1S9	X650	
151	0	2	2	2	2	2	2	2	2	2	2		A
153	2	0	2	2	2	2	2	2	2	2	2		
155	2	2	0	2	3	3	2	2	2	2	2		
160	2	2	2	0	2	2	2	2	2	2	2		
162	2	2	3	2	0	3	2	2	2	2	0		
1 SB	2	2	3	2	3	0	2	2	2	2	0		
175	2	2	2	2	2	2	0	2	2	2	0		
177	2	2	2	2	2	2	2	0	2	2	2		
ISO	2	2	2	2	2	2	2	2	0	2	2		
183	2	2	2	2	2	2	2	2	2	0	0		
129	2	2	2	2	0	0	0	2	2	0	0		
650	2	2	0	0	0	0	0	0	0	0	0		
1579	2	2	2	2	2	2	2	2	2	2	2		V
Environment    History Connections		= r
-* y I fj#» Import Dataset - I		List -
1 Global Environment -	I*	
Data		
Odf                     27 obs. of 27 variables		
		
Files    Plots Packages		Help Viewer		= E
b|	Install    ® Update			I I ©
	Name Description		Version	1
User Library				
□	abind	Combine Multidimensional Arrays	1.4-5	w
□	acepack	ACE and AVASfor Selecting Multiple Regression Transformations	1.4.1	©
TT	antiword	Extract Text from Microsoft Word Documents	1.1	©
□	assertthat	Easy Pre and Post Assertions	0.2.0	©
□	audio	Audio Interface for R	0.1-5	©
□	backports	Reimplementations of Functions Introduced Since R-3.0.0	1.1.2	©
TT	base64enc	Tools for baseS4 encoding	0.1-3	©
□	beepr	Easily Play Notification Sounds on any Platform	1.2	©
□	3H	Boost C + + Header Files	1.66.0-1	©
□	bindr	Parametrized Active Bindings	0.1.1	©
□	bindrcpp	An 'Repp' Interface to Active Bindings	0.2.2	©
□	bit	A Class for Vectors of 1 -Bit Booleans	1.1-13	©
TT	bit64	A S3 Class for Vectors of 64bit Integers	0.9-7	©
□	bitops	Bitwise Operations	1.0-6	©
□	blob	A Simple S3 Class for Representing Vectors of Binary Data [BLOBS']	1.1.1	©
TT	brew	Templating Framework for Report Generation	1.0-6	©
□	ca	Simple, Multiple and Joint Correspondence Analysis	0.70	© V
RStudio
Eile   Edit  Code  View Elots
Session   Build   Debug   Profile  lools EJelp
'—■ Go to file/function I BS - Addins
df
X151
X133
X133
X160
XI62
XI63
XI75
XI77
X160
XI33
XI S3
XS50
Environment    History Connections
kJ    P* Import Dataset - £ 1 Global Environment -
? I Project: (None] ■
List -
														Data	
153	2	0	2	2	2	2	2	2	2	2	2			df                     27 obs. of 27 variables	
155	2	2	0	2	3	3	2	2	2	2	2				
160	2	2	2	0	2	2	2	2	2	2	2				
162	2	2	3	2	0	3	2	2	2	2	0				
1 SB	2	2	3	2	3	0	2	2	2	2	0				
175	2	2	2	2	2	2	0	2	2	2	0				
177	2	2	2	2	2	2	2	0	2	2	2				
180	2	2	2	2	2	2	2	2	0	2	2				
183	2	2	2	2	2	2	2	2	2	O	0			Files    Plots    Packages    Help Viewer	= T
129	2	2	2	2	0	0	0	2	2	0	0			Ol Install    ® Update	
650	2	2	0	0	0	0	0	0	0	0	0			Name Description	Version
1579	2	2	2	2	2	2	2	2	2	2	2			User Library	
Showing 1 to 15 of 27 entries
Console Terminal
> str(df) I 'data.frame'
27 obs. of   27 variables:
•p		XML	a				L	/	z	/	/	/
$	X153	int	2	e	2	2	2	2	2	2	2	2
$	X155	int	2	2	e	2	3	3	2	2	2	2
$	X160	int	2	2	2	e	2	2	2	2	2	2
$	X162	int	2	2	3	2	e	3	2	2	2	2
$	X163	int	2	2	3	2	3	e	2	2	2	2
$	X175	int	2	2	2	2	2	2	e	2	2	2
$	X177	int	2	2	2	2	2	2	2	e	2	2
$	xise	int	2	2	2	2	2	2	2	2	e	2
$	X1S3	int	2	2	2	2	2	2	2	2	2	e
$	X1S9	int	2	2	2	2	e	e	e	2	2	e
j.		■	_	_	_	_						
u
□
□
□
□
□
□
□
□
abind acepack
antiword assertthat audio backports
base64enc
beepr
BH
Combine Multidimensional Arrays
ACE and AVAS for Selecting Multiple Regression Transfo—lations
Extract Text from Microsoft Word Documents Easy Pre and Post Assertions Audio Interface for R
Reimplementations of Functions Introduced Since R-3.0.0
Tools for baseS4 encoding
Easily Play Notification Sounds on any Platform
Boost C + + Header Files
□
□
□
□
bindr bindrcpp bit bit64
O bltops
blob
□
□
b'6'.V
Parametrized Active Bindings An 'Repp' Interface to Active Bindings A Class for Vectors of 1 -Bit Booleans A S3 Class for Vectors of 64bit Integers Bitwise Operations
A Simple S3 Class for Representing Vectors of Binary
Data (BLOBS'}_
Templating Framework for Report Generation Simple, Multiple and Joint Correspondence Analysis
1.4-5 1.4.1
1.1
0.2.0 0.1-5 1.1.2
0.1-3 1.2
1.66.0-1
0.1.1
0.2.2
1.1-13
0.9-7
1.0-6
1.1.1
1.0-6 0.70
©
©
©
©
©
©
©
©
©
©
©
©
© v
Data conversions
• Data frame may be converted to other object types
• Function as . matrix () turns DF to matrix
• Function as . list () will turn DF into list of vectors
• Other object types may be converted to a data frame as well
• Function as . data. frame ()
Data conversions: DF to matrix
• Data are loaded as data frames by default - for
networks, conversion is necessary
• Class of data needs to be considered beforehand
• If text included, the whole matrix will be coerced to character
• Conversion of data classes after the DF conversion is painful - needs to be done column by column
mat <- as.matrix(df)
RStudio
File   Edit   Code   View   Plots   Session   Build   Debug   Profile   lools Help Q   '   Qb,\   t3? " i_i Go to file/function ut - Addins -
£■1 Project: [None] -
df
Filter
Showing 1 to 15 of 27 entries
Console Terminal
C :/U s ers/ L u ka s/ D o wn I c a d s/
> str(df) 'data.fr $ X151
$ X153 $ X155 $ X160 $ X162 $ X163 $ X175 $ X177
$ xise
$ X1S3 $ X1S9
int int int int int int int int int int int
27 2
e
2 2 2 2 2 2 2 2 2
obs. 2 2
of 27 variables: 2 2 2 2 2 2
2 2 2 2 2 2
3 3 2 2 2 2
2 2 2 2 2 2 9 3 2 2 2 2
3 0 2 2 2 2 2 2 0 2 2 2 2 2 2 0 2 2 2 2 2 2 0 2 2 2 2 2 2 0 0 0 0 2 2 0
	X151	XI53	XI55	XI60	XI62	XI63	XI75	XI77	X1S0	X13J	X1S9	X650	
151	0	2	2	2	2	2	2	2	2	2	2		A
153	2	0	2	2	2	2	2	2	2	2	2		
155	2	2	0	2	3	3	2	2	2	2	2		
160	2	2	2	0	2	2	2	2	2	2	2		
162	2	2	3	2	0	3	2	2	2	2	0		
1 SB	2	2	3	2	3	0	2	2	2	2	0		
175	2	2	2	2	2	2	0	2	2	2	0		
177	2	2	2	2	2	2	2	0	2	2	2		
ISO	2	2	2	2	2	2	2	2	0	2	2		
183	2	2	2	2	2	2	2	2	2	0	0		
129	2	2	2	2	0	0	0	2	2	0	0		
650	2	2	0	0	0	0	0	0	0	0	0		
1579	2	2	2	2	2	2	2	2	2	2	2		V
Environment    History Connections		= r
-* y I fj#» Import Dataset - I		List -
1 Global Environment -	I*	
Data		
Odf                     27 obs. of 27 variables		
		
Files    Plots Packages		Help Viewer		= E
oj	Install    ® Update			I I ©
	Name Description		Version	1
User Library				
□	abind	Combine Multidimensional Arrays	1.4-5	w
□	acepack	ACE and AVASfor Selecting Multiple Regression Transformations	1.4.1	©
TT	antiword	Extract Text from Microsoft Word Documents	1.1	©
□	assertthat	Easy Pre and Post Assertions	0.2.0	©
□	audio	Audio Interface for R	0.1-5	©
□	backports	Reimplementations of Functions Introduced Since R-3.0.0	1.1.2	©
TT	base64enc	Tools for baseS4 encoding	0.1-3	©
□	beepr	Easily Play Notification Sounds on any Platform	1.2	©
□	3H	Boost C + + Header Files	1.66.0-1	©
□	bindr	Parametrized Active Bindings	0.1.1	©
□	bindrcpp	An 'Repp' Interface to Active Bindings	0.2.2	©
□	bit	A Class for Vectors of 1 -Bit Booleans	1.1-13	©
□	bit64	A S3 Class for Vectors of 64bit Integers	0.9-7	©
□	bitops	Bitwise Operations	1.0-6	©
□	blob	A Simple S3 Class for Representing Vectors of Binary Data [BLOBS']	1.1.1	©
TT	brew	Templating Framework for Report Generation	1.0-6	©
□	ca	Simple, Multiple and Joint Correspondence Analysis	0.70	© V
Data conversions: matrix to DF
• Inconvenient process
• Argument stringsAsFactors is important -otherwise any text becomes factor variable
• Data class of matrix will be preserved
• No automatic recognition built in on conversion
• If matrix is unnamed, column names are assigned automatically
mat2df <- as.data.frame(mat)
mat2df <- as.data.frame(mat,  stringsAsFactors = FALSE)
Names of rows and columns
• Column names are an issue in data frames
• Data frame columns must have proper column (variable) names
• Names starting with number are not allowed (default transformation behavior to "X#")
• Missing column names lead to automatically generated
names (VI, V2,Vn)
• Conversion (e.g. from list) might result into crazy column names
Names of rows and columns
• If issue with names is present, renaming needs to follow
• Functions rownames () and colnames () allow to access existing names
• Renaming is counterintuitive - we need to assign vector with names to the function result
• It must be of a same length as number of columns
colnames(df)  <- c("varl"  ,   "var2"  ,   ...  , "varN")
Names of rows and columns
• Names may be generated automatically using
paste () orpasteOO functions - these functions collapse text bits together
• Function paste () adds spaces between texts
• Function pasteO () collapses texts without spaces
colnames(df)  <- pasteO("actor"  , 1:27)
* In case of a matrix, each dimension needs to be named separately
colnames(mat) <- pasteO("actor" , 1:27)
colnames(mat)  <- rownames(mat)
Data export
• Export of entire workspace
• Export of particular objects
• R native files
• Structured data (tables)
• Unstructured data
Data export: saving entire workspace
• Function save . image ()
• Rdata format
• No additional arguments required
save.image(file = "workspace 2018 07 04.rdata")
File   Edit  Code   View £lots
Session   Build   Debug   Profile   Tools Help
LJ     (4 Go to file/function I BS * Addins -
Console Terminal
C:/Users/Lukas/Downloads/
> View(df)
>
BS«** _													
	i <a	"7 Filter											
	XI51	X1S3	XI55	XI60	XI62	XI63	X175	XI77	X16D	XI81		XI89	X650
151	0	2	2	2	2	2	2	2	2	2			
153	2	0	2	2	2	2	2	2	2	2		2	
155	2	2	0	2	3	3	2	2	2			2	
160	2	2	2	0	2	2	2	2	2	2		2	
162	2	2	3	2	0	3	2	2	2	2		0	
163	2	2	3	2	3	0	2	2	2	2		0	1
175	2	2	2	2	2	2	0	2	2	2		0	
177	2	2	2	2	2	2	2	0	2	2		2	
ISO	2	2	2	2	2	2	2	2	0	2		2	
1S3	2	2	2	2	2	2	2	2	2	0		0	
189	2	2	2	2	0	0	0	2	2	0		0	
650	2	2	0	0	0	0	0	0	0	0		0	
1579	2	2	2	2	2	2	2	2	2	2		2	V
													
<													>
Showing 1 to 15 of 27 entries													
Environment    History Connections
t2* bJ    f1^* Import Dataset -'Global Environment -
Data df
^ Project: (None) -List -
27 obs. of 27 variables
Files	Plots Packages	Help Viewer		= T
6| Install    (£) Update		Q.		
	Name	Description	Version	
User Library				
□	abind	Combine Multidimensional Arrays	1.4-5	V
□	acepack	ACE and AVASfor Selecting Multiple Regression Transformations	1.4,1	G
□	antiword	Extract Text from Microsoft Word Documents	1.1	Q
□	assertthat	Easy Pre and Post Assertions	0.2.0	Q
□	a u die	Audio Interface for R	0.1-5	e
□	backports	Reimplementations of Functions Introduced Since R-3.0.0	1.1.2	0
□	base64enc	Tools for base64 encoding	0,1-3	Q
□	beepr	Easily Play Notification Sounds on any Platform	1.2	O
□	3H	Boost C + + Header Files	1,66.0-1	
□	bindr	Parametrized Active Bindings	0,1,1	©
□	bindrepp	An 'Repp' Interface to Active Bindings	0.2.2	G
□	bit	A Class for Vectors of 1 -Bit Booleans	1,1-13	G
	bitS4	A S3 Class for Vectors of 64bit Integers	0,9-7	G
□	bitops	Bitwise Operations	1,0-6	G
□	blob	A Simple S3 Class for Representing Vectors of Binary Data ('BLOBS')	1.1.1	G
□	bre'.v	Templating Framework for Report Generation	1.0-6	V
□	ca	Simple, Multiple and Joint Correspondence Analysis	0.70	
Data export: saving particular object as Rdata
• Function save ()
• Rdata is R native format
• Preserves the object as is, with its object name
• Allows to avoid export and import issues
save(df,
file = "BALIBOMBING export.rdata")
Data export: saving tabular data
• Function write . table ()
• Object which is exported has to be specified
• Otherwise similar to read. table ()
write.table(df,
"BALIBOMBING_export.csv",
sep = 11, 11 ,
row.names = TRUE,
col.names = TRUE,
fileEncoding = "UTF-8")
Data export: saving unstructured data
• Function writeLines ()
• Similar to readLines ()
• Basically no arguments
writeLines(df,
"BALIBOMBING export.txt")
Other input and output options
• Built-in CSV-specific functions
• read, csv () and write . csv () functions
• read, csv () requires less arguments than read. table () but has more limited functionality
• Libraries "xlsx" or "openxlsx" for XLSX input
• Both packages contain functions read, xlsx () and write . xlsx () - similar to read, table ()
• Package "readtext" designed to read unstructured text data (PDFs, Word documents, etc.)
• Other packages for specific formats (XML, HTML, Json, SQL,...)
Practice 1
• Download the package "MEB433_434_03A_practice.zip" into your computer
• Unpack it into any folder
• Set the folder as a working directory
• Import the data "nrg_122a.csv" into R
• Explore and adjust the data set in a text editor, if necessary
• Achieve the following
• Dataset has proper column names
• Missing values are treated correctly (find function arguments)
• All columns are numeric (there's a catch here)
Practice 2
• Get rid of the summary rows in the data frame
• Get rid of the missing values for the last year
• Extract only the last 3 years into a separate object
• Export the subset in rdata format
• Export the subset in CSV format