R Programming: Importing Data In R
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The document provides a comprehensive guide to learning R programming for data analysis. It covers course modules, data handling concepts, including importing data from various file types, and functions for reading data from console and files. Specific functions are detailed with their syntax and usage examples for practical understanding.
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Slide 7
scan() (2/4)
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Examples
> # example 1
> x <- scan()
1: 1
2: 2
3: 3
4:
Read 3 items
# to end input, do not enter anything.
> x
[1] 1 2 3
> typeof(x)
[1] "double"
# if numbers are entered, they will be stored as double. In the next example, we will learn
how to store numbers as integers.](https://image.slidesharecdn.com/importingdatainr-150415080314-conversion-gate01/85/R-Programming-Importing-Data-In-R-7-320.jpg)
![r-squared
Slide 8
scan() (3/4)
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Examples
> # example 2
> x <- scan("", what = integer())
1: 1
2: 2
3: 3
4:
Read 3 items
# mention the data type in the what argument to store the data in the preferred mode.
> x
[1] 1 2 3
> typeof(x)
[1] "integer"](https://image.slidesharecdn.com/importingdatainr-150415080314-conversion-gate01/85/R-Programming-Importing-Data-In-R-8-320.jpg)
![r-squared
Slide 9
scan() (4/4)
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Examples
> # example 3
> x <- scan("", what = list(name = "", age = 0))
1: Jovial 28
2: Manual 27
3: Funnel 25
4: Tunnel 29
5:
Read 4 records
# suppose we want the user to enter multiple attributes and store the input in a list. Use
list in the what argument with the names for the attributes.
> x
$name
[1] "Jovial" "Manual" "Funnel" "Tunnel"
$age
[1] 28 27 25 29](https://image.slidesharecdn.com/importingdatainr-150415080314-conversion-gate01/85/R-Programming-Importing-Data-In-R-9-320.jpg)
![r-squared
Slide 11
readline() (2/3)
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Examples
> # example 1
> x <- readline(prompt = "Enter your name: ")
Enter your name: Jovial
> x
[1] "Jovial"
> class(x)
[1] "character"
# input is stored as character type. It has to be converted to other data types as necessary.
In the next example, we will input a number and then store it as an integer.](https://image.slidesharecdn.com/importingdatainr-150415080314-conversion-gate01/85/R-Programming-Importing-Data-In-R-11-320.jpg)
![r-squared
Slide 12
readline() (3/3)
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Examples
> # example 2
> x <- readline(prompt = "Enter your age: ")
Enter your age: 28
> x
[1] "28"
> class(x)
[1] "character"
> x <- as.integer(x)
> x
[1] 28](https://image.slidesharecdn.com/importingdatainr-150415080314-conversion-gate01/85/R-Programming-Importing-Data-In-R-12-320.jpg)
![r-squared
Slide 16
scan() (3/5)
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Examples
> # example 1
> scan("words.txt", what = character(), skip = 2, nlines = 2,
+ quiet = TRUE)
[1] "Morbi" "consequat" "commodo" "orci" "ut" "volutpat."
[7] "Sed" "accumsan" "eleifend" "egestas." "Nullam" "ac"
[13] "posuere" "eros." "Donec" "rutrum" "gravida" "felis,"
[19] "quis" "fermentum" "orci." "Pellentesque" "purus" "lacus,"
[25] "tincidunt" "eget" "enim" "ut," "facilisis" "rutrum"
[31] "odio."
# read two lines from the file “words.txt” as type character after skipping the first two
lines and do not print the number of lines read on the console.](https://image.slidesharecdn.com/importingdatainr-150415080314-conversion-gate01/85/R-Programming-Importing-Data-In-R-16-320.jpg)
![r-squared
Slide 17
scan() (4/5)
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Examples
> # example 2
> scan("words.txt", what = list("", ""), skip = 2, nlines = 2, sep = " ",
+ quiet = TRUE)
[[1]]
[1] "Morbi" "commodo" "ut" "Sed" "eleifend" "Nullam" "posuere"
[8] "Donec" "gravida" "quis" "orci." "purus" "tincidunt" "enim"
[15] "facilisis" "odio."
[[2]]
[1] "consequat" "orci" "volutpat." "accumsan" "egestas." "ac"
[7] "eros." "rutrum" "felis," "fermentum" "Pellentesque" "lacus,"
[13] "eget" "ut," "rutrum" ""
# read two lines from the file “words.txt” as a list, after skipping the first two lines and
do not print the number of lines read on the console.](https://image.slidesharecdn.com/importingdatainr-150415080314-conversion-gate01/85/R-Programming-Importing-Data-In-R-17-320.jpg)
![r-squared
Slide 18
scan() (5/5)
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Examples
> # example 3
> scan("words.txt", what = list("", "", ""), skip = 2, nlines = 3, sep = " ",
+ quiet = TRUE)
[[1]]
[1] "Morbi" "orci" "Sed" "egestas." "posuere" "Donec" "felis,"
[8] "orci." "lacus," "enim" "rutrum" "Donec" "tincidunt" "eu,"
[15] "tortor." "turpis" "bibendum"
[[2]]
[1] "consequat" "ut" "accumsan" "Nullam" "eros." "rutrum"
[7] "quis" "Pellentesque" "tincidunt" "ut," "odio." "mi"
[13] "a" "euismod" "In" "vel" "posuere."
[[3]]
[1] "commodo" "volutpat." "eleifend" "ac" "" "gravida"
[7] "fermentum" "purus" "eget" "facilisis" "" "urna,"
[13] "sollicitudin" "non" "dignissim" "lorem" ""
# read three lines from the file “words.txt” as a list, after skipping the first two lines
and do not print the number of lines read on the console.](https://image.slidesharecdn.com/importingdatainr-150415080314-conversion-gate01/85/R-Programming-Importing-Data-In-R-18-320.jpg)
![r-squared
Slide 20
readLines() (2/3)
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Examples
> # example 1
> readLines("words.txt")
[1] "Lorem ipsum dolor sit amet, consectetur adipiscing elit. In sodales nulla quis interdum
dictum. "
[2] "Maecenas molestie suscipit libero lobortis ornare. Nam quam magna, tincidunt id
vulputate nec, elementum ac lorem. "
[3] "Morbi consequat commodo orci ut volutpat. Sed accumsan eleifend egestas. Nullam ac
posuere eros. "
. . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . .
[15] "Vivamus pulvinar consectetur tellus, quis mollis libero lobortis at. "
[16] "Quisque tincidunt purus fermentum augue auctor ultricies."
[17] ""
# reads all the lines from the file](https://image.slidesharecdn.com/importingdatainr-150415080314-conversion-gate01/85/R-Programming-Importing-Data-In-R-20-320.jpg)
![r-squared
Slide 21
readLines() (3/3)
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Examples
> # example 2
> readLines("words.txt", n = 5)
[1] "Lorem ipsum dolor sit amet, consectetur adipiscing elit. In sodales nulla quis interdum
dictum. "
[2] "Maecenas molestie suscipit libero lobortis ornare. Nam quam magna, tincidunt id
vulputate nec, elementum ac lorem. "
[3] "Morbi consequat commodo orci ut volutpat. Sed accumsan eleifend egestas. Nullam ac
posuere eros. "
[4] "Donec rutrum gravida felis, quis fermentum orci. Pellentesque purus lacus, tincidunt
eget enim ut, facilisis rutrum odio. "
[5] "Donec mi urna, tincidunt a sollicitudin eu, euismod non tortor. In dignissim turpis vel
lorem bibendum posuere. "
# reads the first 5 lines from the file.](https://image.slidesharecdn.com/importingdatainr-150415080314-conversion-gate01/85/R-Programming-Importing-Data-In-R-21-320.jpg)
R Programming: Importing Data In R
- 1. r-squared Slide 1 www.r-squared.in/rprogramming R Programming Learn the fundamentals of data analysis with R.
- 2. r-squared Slide 2 Course Modules www.r-squared.in/rprogramming ✓ Introduction ✓ Elementary Programming ✓ Working With Data ✓ Selection Statements ✓ Loops ✓ Functions ✓ Debugging ✓ Unit Testing
- 3. r-squared Slide 3 Working With Data www.r-squared.in/rprogramming ✓ Data Types ✓ Data Structures ✓ Data Creation ✓ Data Info ✓ Data Subsetting ✓ Comparing R Objects ✓ Importing Data ✓ Exporting Data ✓ Data Transformation ✓ Numeric Functions ✓ String Functions ✓ Mathematical Functions
- 4. r-squared Slide 4 Importing Data In R www.r-squared.in/rprogramming Objectives In this module, we will learn to: ● Read data from the console ● Read data from files ● Import data from ○ Text/Excel/CSV files ○ Stata/SAS/SPSS files ● Load .Rdata files ● Source R scripts
- 5. r-squared Slide 5 Read Data From Console www.r-squared.in/rprogramming In this section, we will learn to read data from the console interactively and store them as R objects using the following functions: ✓ scan ✓ readline
- 6. r-squared Slide 6 scan() (1/4) www.r-squared.in/rprogramming Description: scan() allows user to input data from console or from a file and stores the input in a vector or list. Syntax: x <- scan() # stores input as vector x <- scan("", what = integer()) # stores input as integer x <- scan("", what = list()) # stores input as list Returns: A vector or list of the input data. Documentation help(scan)
- 7. r-squared Slide 7 scan() (2/4) www.r-squared.in/rprogramming Examples > # example 1 > x <- scan() 1: 1 2: 2 3: 3 4: Read 3 items # to end input, do not enter anything. > x [1] 1 2 3 > typeof(x) [1] "double" # if numbers are entered, they will be stored as double. In the next example, we will learn how to store numbers as integers.
- 8. r-squared Slide 8 scan() (3/4) www.r-squared.in/rprogramming Examples > # example 2 > x <- scan("", what = integer()) 1: 1 2: 2 3: 3 4: Read 3 items # mention the data type in the what argument to store the data in the preferred mode. > x [1] 1 2 3 > typeof(x) [1] "integer"
- 9. r-squared Slide 9 scan() (4/4) www.r-squared.in/rprogramming Examples > # example 3 > x <- scan("", what = list(name = "", age = 0)) 1: Jovial 28 2: Manual 27 3: Funnel 25 4: Tunnel 29 5: Read 4 records # suppose we want the user to enter multiple attributes and store the input in a list. Use list in the what argument with the names for the attributes. > x $name [1] "Jovial" "Manual" "Funnel" "Tunnel" $age [1] 28 27 25 29
- 10. r-squared Slide 10 readline() (1/3) www.r-squared.in/rprogramming Description: readline() prompts the user for an input and stores the input as a character vector. Syntax: readline(prompt = "") Returns: A character vector of the input data. Documentation help(readline)
- 11. r-squared Slide 11 readline() (2/3) www.r-squared.in/rprogramming Examples > # example 1 > x <- readline(prompt = "Enter your name: ") Enter your name: Jovial > x [1] "Jovial" > class(x) [1] "character" # input is stored as character type. It has to be converted to other data types as necessary. In the next example, we will input a number and then store it as an integer.
- 12. r-squared Slide 12 readline() (3/3) www.r-squared.in/rprogramming Examples > # example 2 > x <- readline(prompt = "Enter your age: ") Enter your age: 28 > x [1] "28" > class(x) [1] "character" > x <- as.integer(x) > x [1] 28
- 13. r-squared Slide 13 Read Data From Files www.r-squared.in/rprogramming In this section, we will learn to read data from files using the following functions: ✓ scan ✓ readLines
- 14. r-squared Slide 14 scan() (1/5) www.r-squared.in/rprogramming Description: scan() allows user to input data from console or from a file and stores the input in a vector or list. Syntax: scan(file = "", what = double(), nmax = -1L, n = -1L, sep = "", quote = if (identical(sep, "n")) "" else "'"", dec = ".", skip = 0L, nlines = 0L, na.strings = "NA", flush = FALSE, fill = FALSE, strip.white = FALSE, quiet = FALSE, blank.lines.skip = TRUE, multi.line = TRUE, comment.char = "", allowEscapes = FALSE, fileEncoding = "", encoding = "unknown", text, skipNul = FALSE) Returns: A vector or list of the input data. Documentation help(scan)
- 15. r-squared Slide 15 scan() (2/5) www.r-squared.in/rprogramming Arguments: file: name of the file from which the data must be read. what: mode in which data must be stored. nmax: maximum number of data values or lines to be read from a file. n: maximum number of data values to be read. sep: delimiter skip: number of lines to be skipped before reading reading data from a file. nlines: maximum number of lines to be read from a file. quiet: how many items have been read. blank.lines.skip: if blank lines must be skipped. multi.line: whether all lines must appear in one line or multi-line.
- 16. r-squared Slide 16 scan() (3/5) www.r-squared.in/rprogramming Examples > # example 1 > scan("words.txt", what = character(), skip = 2, nlines = 2, + quiet = TRUE) [1] "Morbi" "consequat" "commodo" "orci" "ut" "volutpat." [7] "Sed" "accumsan" "eleifend" "egestas." "Nullam" "ac" [13] "posuere" "eros." "Donec" "rutrum" "gravida" "felis," [19] "quis" "fermentum" "orci." "Pellentesque" "purus" "lacus," [25] "tincidunt" "eget" "enim" "ut," "facilisis" "rutrum" [31] "odio." # read two lines from the file “words.txt” as type character after skipping the first two lines and do not print the number of lines read on the console.
- 17. r-squared Slide 17 scan() (4/5) www.r-squared.in/rprogramming Examples > # example 2 > scan("words.txt", what = list("", ""), skip = 2, nlines = 2, sep = " ", + quiet = TRUE) [[1]] [1] "Morbi" "commodo" "ut" "Sed" "eleifend" "Nullam" "posuere" [8] "Donec" "gravida" "quis" "orci." "purus" "tincidunt" "enim" [15] "facilisis" "odio." [[2]] [1] "consequat" "orci" "volutpat." "accumsan" "egestas." "ac" [7] "eros." "rutrum" "felis," "fermentum" "Pellentesque" "lacus," [13] "eget" "ut," "rutrum" "" # read two lines from the file “words.txt” as a list, after skipping the first two lines and do not print the number of lines read on the console.
- 18. r-squared Slide 18 scan() (5/5) www.r-squared.in/rprogramming Examples > # example 3 > scan("words.txt", what = list("", "", ""), skip = 2, nlines = 3, sep = " ", + quiet = TRUE) [[1]] [1] "Morbi" "orci" "Sed" "egestas." "posuere" "Donec" "felis," [8] "orci." "lacus," "enim" "rutrum" "Donec" "tincidunt" "eu," [15] "tortor." "turpis" "bibendum" [[2]] [1] "consequat" "ut" "accumsan" "Nullam" "eros." "rutrum" [7] "quis" "Pellentesque" "tincidunt" "ut," "odio." "mi" [13] "a" "euismod" "In" "vel" "posuere." [[3]] [1] "commodo" "volutpat." "eleifend" "ac" "" "gravida" [7] "fermentum" "purus" "eget" "facilisis" "" "urna," [13] "sollicitudin" "non" "dignissim" "lorem" "" # read three lines from the file “words.txt” as a list, after skipping the first two lines and do not print the number of lines read on the console.
- 19. r-squared Slide 19 readLines() (1/3) www.r-squared.in/rprogramming Description: readLines() allows user to input data from console or from a file and stores the input in a vector or list. Syntax: readLines(file_name) Returns: A vector of the input data. Documentation help(readLines)
- 20. r-squared Slide 20 readLines() (2/3) www.r-squared.in/rprogramming Examples > # example 1 > readLines("words.txt") [1] "Lorem ipsum dolor sit amet, consectetur adipiscing elit. In sodales nulla quis interdum dictum. " [2] "Maecenas molestie suscipit libero lobortis ornare. Nam quam magna, tincidunt id vulputate nec, elementum ac lorem. " [3] "Morbi consequat commodo orci ut volutpat. Sed accumsan eleifend egestas. Nullam ac posuere eros. " . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [15] "Vivamus pulvinar consectetur tellus, quis mollis libero lobortis at. " [16] "Quisque tincidunt purus fermentum augue auctor ultricies." [17] "" # reads all the lines from the file
- 21. r-squared Slide 21 readLines() (3/3) www.r-squared.in/rprogramming Examples > # example 2 > readLines("words.txt", n = 5) [1] "Lorem ipsum dolor sit amet, consectetur adipiscing elit. In sodales nulla quis interdum dictum. " [2] "Maecenas molestie suscipit libero lobortis ornare. Nam quam magna, tincidunt id vulputate nec, elementum ac lorem. " [3] "Morbi consequat commodo orci ut volutpat. Sed accumsan eleifend egestas. Nullam ac posuere eros. " [4] "Donec rutrum gravida felis, quis fermentum orci. Pellentesque purus lacus, tincidunt eget enim ut, facilisis rutrum odio. " [5] "Donec mi urna, tincidunt a sollicitudin eu, euismod non tortor. In dignissim turpis vel lorem bibendum posuere. " # reads the first 5 lines from the file.
- 22. r-squared Slide 22 Import Data Files www.r-squared.in/rprogramming In this section, we will learn to import the following data files: ✓ Text file ✓ Excel/CSV file ✓ Stata file ✓ SAS file ✓ SPSS file
- 23. r-squared Slide 23 Importing Text File www.r-squared.in/rprogramming Description: read.table() reads a file in table format and creates a data frame from it. Syntax: read.table(file_name, header, sep) Returns: A data frame. Documentation help(read.table)
- 24. r-squared Slide 24 read.table() www.r-squared.in/rprogramming Examples > # example 1 > # read data from a semicolon delimited file and retain the column names > text_data <- read.table("data.txt", header = TRUE, sep = ";") > # example 2 > # read data from a comma delimited file and retain the column names > text_data1 <- read.table("data1.txt", header = TRUE, sep = ",") > # example 3 > # read data from a tab delimited file and retain the column names > text_data2 <- read.table("data2.txt", header = TRUE, sep = "t")
- 25. r-squared Slide 25 read.csv() www.r-squared.in/rprogramming Description: read.csv() reads a CSV file in table format and creates a data frame from it. Syntax: read.csv(file, header = TRUE, sep = ",", quote = """, dec = ".", fill = TRUE, comment.char = "", ...) Returns: A data frame. Documentation help(read.csv)
- 26. r-squared Slide 26 read.csv() www.r-squared.in/rprogramming Examples > # example 1 > # read data from a CSV file and retain the column names > data_csv <- read.csv("data.csv", header = TRUE) > # example 2 > # read data from a CSV file without the column names > data_csv <- read.csv("data.csv", header = FALSE) > # example 3 > # read data from a CSV file and retain the column names and add blank fields > # when rows are of unequal length > data_csv <- read.csv("data.csv", header = TRUE, fill = TRUE)
- 27. r-squared Slide 27 read.xls() www.r-squared.in/rprogramming Description: read.xls() reads an excel file in table format and creates a data frame from it. You need to install the gdata package in order to use the read.xls() function. Syntax: read.xls(file, sheet) Returns: A data frame. Documentation: library(gdata) help(read.xls)
- 28. r-squared Slide 28 read.xls() www.r-squared.in/rprogramming Examples > # example 1 > # read data from a excel file > data_xls <- read.xls("data.csv") > # example 2 > # read data from a particular sheet in a excel file > data_xls <- read.xls("data.csv", sheet = 1)
- 29. r-squared Slide 29 Stata File www.r-squared.in/rprogramming Description read.dta() reads a Stata binary file into a data frame. Package Install the foreign package to import stata files. Syntax read.csv(file, convert.dates = TRUE, convert.factors = TRUE, missing.type = FALSE, convert.underscore = FALSE, warn.missing.labels = TRUE) Returns A data frame. Documentation help(read.dta)
- 30. r-squared Slide 30 read.dta() www.r-squared.in/rprogramming Examples > # example 1 > install.packages("foreign") > library(foreign) > data_stata <- read.dta("auto.dta")
- 31. r-squared Slide 31 SPSS File www.r-squared.in/rprogramming Description read.spss() reads a SPSS file into a data frame. Package Install the foreign package to import stata files. Syntax read.spss(file, use.value.labels = TRUE, to.data.frame = FALSE, max.value.labels = Inf, trim.factor.names = FALSE, trim_values = TRUE, reencode = NA, use.missings = to.data.frame) Returns A data frame. Documentation help(read.spss)
- 32. r-squared Slide 32 read.spss() www.r-squared.in/rprogramming Examples > # example 1 > install.packages("foreign") > library(foreign) > data_spss <- read.spss("binary.sav")
- 33. r-squared Slide 33 SAS File www.r-squared.in/rprogramming Description read.sas7bdat() reads SAS files in the sas7bdat data format into a dataframe. Package Install the sas7bdat package to import stata files. Syntax: read.sas7bdat(file, debug=FALSE) Returns: A data frame. Documentation help(read.sas7bdat)
- 34. r-squared Slide 34 read.sas7bdat() www.r-squared.in/rprogramming Examples > # example 1 > install.packages("sas7bdat") > library(sas7bdat) > data_sas <- read.sas7bdat("crime.sas7bdat")
- 35. r-squared Slide 35 load() www.r-squared.in/rprogramming Description load() reloads saved datasets and workspaces. Datasets and workspaces have the extension .RData Syntax: load(file) Returns: R object or workspace. Documentation help(load) Example > load("x.RData")
- 36. r-squared Slide 36 source() www.r-squared.in/rprogramming Description source() reads R codes from a file and makes those codes available in the current session. R scripts have the extension .R Syntax: source(file_name, file_path) Returns Codes from a R file. Documentation help(source) Example > source("functions.R")
- 37. r-squared Slide 37 Next Steps... www.r-squared.in/rprogramming In the next unit, we will learn to export data from R: ● Output data to the console ● Output data to files ● Export data into text/CSV files ● Save R objects
- 38. r-squared Slide 38 Connect With Us www.r-squared.in/rprogramming Visit r-squared for tutorials on: ● R Programming ● Business Analytics ● Data Visualization ● Web Applications ● Package Development ● Git & GitHub