This document discusses various functions in R for exporting data, including print(), cat(), paste(), paste0(), sprintf(), writeLines(), write(), write.table(), write.csv(), and sink(). It provides descriptions, syntax, examples, and help documentation for each function. The functions can be used to output data to the console, files, or save R objects. write.table() and write.csv() convert data to a data frame or matrix before writing to a text file or CSV. sink() diverts R output to a file instead of the console.

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R Programming
Learn the fundamentals of data analysis with R.

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Course Modules
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✓ Introduction
✓ Elementary Programming
✓ Working With Data
✓ Selection Statements
✓ Loops
✓ Functions
✓ Debugging
✓ Unit Testing

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Working With Data
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✓ 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

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Exporting Data From R
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Objectives
In this module, we will learn to:
● Output data to the console
● Output data to files
● Export data into text/CSV files
● Save R objects

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Output Data To Console
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In this section, we will learn to output data to the console using the following functions:
✓ print
✓ cat
✓ paste
✓ paste0
✓ sprintf

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print()
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Description
print() is a very basic function and as the name suggest it prints its arguments.
Syntax
print(x, ...)
Returns
Prints its arguments
Documentation
help(print)

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print()
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Examples
> # example 1
> x <- 3
> print(x)
[1] 3
> x
[1] 3
> # example 2
> name <- "Jovial"
> lname <- "Mann"
> print(name, lname)
Error in print.default(name, lname) : invalid 'digits' argument
> print(c(name, lname))
[1] "Jovial" "Mann"

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cat()
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Description
cat() concatenates its arguments and then outputs them.
Syntax
cat(... , file = "", sep = " ", fill = FALSE, labels = NULL,
append = FALSE)
Returns
Concatenates and outputs its arguments
Documentation
help(cat)

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cat()
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Examples
> # example 1
# output to the console
> name <- "Jovial"
> age <- 28
> cat("Your name is", name, " and you are", age, " years old.")
Your name is Jovial and you are 28 years old.
> # example 2
# output to a file
> name <- "Jovial"
> age <- 28
> cat("Your name is", name, " and you are", age, " years old.", file = "words.txt")

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cat()
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Examples
> # example 3
# difference between print and cat
> fname <- "Jovial"
> lname <- "Mann"
> print(c(fname, lname)) # throws an error
[1] "Jovial" "Mann"
> name <- c(fname, lname)
> name
[1] "Jovial" "Mann"
> name <- "Jovial Mann"
> print(name)
[1] "Jovial Mann"
> cat(fname, lname)
Jovial Mann

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paste()
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Description
paste() converts its arguments to character strings and concatenates them.
Syntax
paste (..., sep = " ", collapse = NULL)
Returns
Character vector
Documentation
help(paste)

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paste()
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Examples
> # example 1
> x <- 1:10
> paste(x)
[1] "1" "2" "3" "4" "5" "6" "7" "8" "9" "10"
> paste(x, collapse = "")
[1] "12345678910"
> # example 2
> x <- LETTERS
> x
[1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" "P" "Q" "R" "S" "T" "U" "V"
[23] "W" "X" "Y" "Z"
> paste(x)
[1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" "P" "Q" "R" "S" "T" "U" "V"
[23] "W" "X" "Y" "Z"
> paste(x, collapse = "")
[1] "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

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paste()
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Examples
> # example 3
> name <- "Jovial"
> age <- 28
> paste(name, age)
[1] "Jovial 28"
> paste(name, age, sep = ",")
[1] "Jovial,28"
> paste(name, age, sep = "")
[1] "Jovial28"

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paste()
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Examples
> # example 4
> alpha <- LETTERS[1:4]
> numeric <- 1:4
> alpha_numeric <- paste(alpha, numeric)
> alpha_numeric
[1] "A 1" "B 2" "C 3" "D 4"
> alpha_numeric <- paste(alpha, numeric, sep = "")
> alpha_numeric
[1] "A1" "B2" "C3" "D4"

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paste0()
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Description
paste0() does the same job as paste but with a blank separator.
Syntax
paste0(..., collapse = NULL)
Returns
Character vector of concatenated values.
Documentation
help(paste0)

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paste0()
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Examples
> # example 1
> alpha <- LETTERS[1:4]
> numeric <- 1:4
> paste0(alpha, numeric)
[1] "A1" "B2" "C3" "D4"
> paste(alpha, numeric, sep = "")
[1] "A1" "B2" "C3" "D4"
> # example 2
> name <- "Jovial"
> age <- 28
> paste0(name, age)
[1] "Jovial28"
> paste(name, age, sep = "")
[1] "Jovial28"

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sprintf()
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Description
sprintf() returns a character vector containing text and objects.
Syntax
sprintf(fmt, ...)
Returns
Character vector
Documentation
help(sprintf)

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sprintf()
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Examples
> # example 1
> name <- "Jovial"
> age <- 28
> sprintf("Your name is %s and you are %d years old", name, age)
[1] "Your name is Jovial and you are 28 years old"
# %s is replaced by the value in name and %d is replaced by value in age. s indicates string
type and d indicates integer type.

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Output Data To File
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In this section, we will learn to output data to a file using the following functions:
✓ writeLines
✓ write
✓ write.table
✓ write.csv
✓ sink
✓ dump

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writeLines()
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Description
writeLines() writes text lines to a connection or a file.
Syntax
writeLines(text, con = stdout(), sep = "n", useBytes = FALSE)
Returns
File with overwritten text.
Documentation
help(writeLines)

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writeLines()
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Examples
> # example 1
> details <- "My name is Jovial."
> writeLines(details, "write.txt")
> readLines("write.txt")
[1] "My name is Jovial."
> # example 2
> details_2 <- "I am 28 years old."
> writeLines(details_2, "write.txt")
> readLines("write.txt")
[1] "I am 28 years old."
# As you might have observed, writeLines overwrites the contents of a file. To append text to
a file, we will use the write function.

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write()
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Description
write() writes/appends data to a file.
Syntax
write(x, file = "data", ncolumns = if(is.character(x)) 1 else 5,
append = FALSE, sep = " ")
Returns
File with appended text.
Documentation
help(write)

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write()
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Examples
> # example 1
> name <- "My name is Jovial."
> write(name, file = "write.txt")
> readLines("write.txt")
[1] "My name is Jovial."
> age <- "I am 28 years old."
> write(age, file = "write.txt", append = TRUE)
> readLines("write.txt")
[1] "My name is Jovial." "I am 28 years old."

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write()
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Examples
> # example 2
> x <- 1:5
> x
[1] 1 2 3 4 5
> write(x, file = "write.txt", append = TRUE)
> readLines("write.txt")
[1] "My name is Jovial." "I am 28 years old." "1 2 3 4 5"
> write(x, file = "write.txt", append = TRUE)
> readLines("write.txt")
[1] "My name is Jovial." "I am 28 years old." "1 2 3 4 5" "1 2 3 4 5"
> write(x, file = "write.txt", append = TRUE, sep = "-")
> readLines("write.txt")
[1] "My name is Jovial." "I am 28 years old." "1 2 3 4 5" "1 2 3 4 5"
[5] "1-2-3-4-5"

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write.table()
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Description
write.table() will convert the data into data.frame or matrix before writing it to a file.
Syntax
write.table(x, file = "", append = FALSE, quote = TRUE, sep = " ", eol =
"n", na = "NA", dec = ".", row.names = TRUE, col.names = TRUE, qmethod =
c("escape", "double"), fileEncoding = "")
Returns
File with data as a data frame or matrix.
Documentation
help(write.table)

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write.table()
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Examples
> # example 1
> m <- matrix(1:9, nrow = 3)
> m
[,1] [,2] [,3]
[1,] 1 4 7
[2,] 2 5 8
[3,] 3 6 9
> # write to a text file
> write.table(m, file = "table.txt")
> readLines("table.txt")
[1] ""V1" "V2" "V3"" ""1" 1 4 7" ""2" 2 5 8"
[4] ""3" 3 6 9"

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write.table()
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Examples
> # example 2
> # write to a csv file
> write.table(m, file = "table.csv")
> readLines("table.csv")
[1] ""V1" "V2" "V3"" ""1" 1 4 7" ""2" 2 5 8"
[4] ""3" 3 6 9"
> # example 3
> # append the transpose of the matrix
> write.table(t(m), file = "table.txt", append = TRUE)
> readLines("table.txt")
[1] ""V1" "V2" "V3"" ""1" 1 4 7" ""2" 2 5 8"
[4] ""3" 3 6 9" ""V1" "V2" "V3"" ""1" 1 2 3"
[7] ""2" 4 5 6" ""3" 7 8 9"

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write.table()
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> # example 4
> # use comma as a separator
> write.table(t(m), file = "table.txt", append = TRUE, sep = ",")
> readLines("table.txt")
[1] ""V1" "V2" "V3"" ""1" 1 4 7" ""2" 2 5 8"
[4] ""3" 3 6 9" ""V1" "V2" "V3"" ""1" 1 2 3"
[7] ""2" 4 5 6" ""3" 7 8 9" ""V1","V2","V3""
[10] ""1",1,2,3" ""2",4,5,6" ""3",7,8,9"
> # example 5
> # without row and column names
> write.table(t(m), file = "table.txt", append = TRUE, row.names = FALSE,
+ col.names = FALSE)
> readLines("table.txt")
[1] ""V1" "V2" "V3"" ""1" 1 4 7" ""2" 2 5 8"
[4] ""3" 3 6 9" ""V1" "V2" "V3"" ""1" 1 2 3"
[7] ""2" 4 5 6" ""3" 7 8 9" ""V1","V2","V3""
[10] ""1",1,2,3" ""2",4,5,6" ""3",7,8,9"
[13] "1 2 3" "4 5 6" "7 8 9"

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write.csv()
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Description
write.csv() will convert the data into data.frame or matrix before writing it to a CSV file.
Syntax
write.csv(data, file, row.names= FALSE)
Returns
CSV file
Documentation
help(write.csv)

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write.csv()
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Examples
> # example 1
> write.csv(mtcars, "mt.csv")
> readLines("mt.csv")
[1]""","mpg","cyl","disp","hp","drat","wt","qsec","vs","am","gear","carb""
[2] ""Mazda RX4",21,6,160,110,3.9,2.62,16.46,0,1,4,4"
[3] ""Mazda RX4 Wag",21,6,160,110,3.9,2.875,17.02,0,1,4,4"
[4] ""Datsun 710",22.8,4,108,93,3.85,2.32,18.61,1,1,4,1"
> # example 2
> # without row names
> write.csv(mtcars, "mt.csv", row.names = FALSE)
> readLines("mt.csv")
[1] ""mpg","cyl","disp","hp","drat","wt","qsec","vs","am","gear","carb""
[2] "21,6,160,110,3.9,2.62,16.46,0,1,4,4"
[3] "21,6,160,110,3.9,2.875,17.02,0,1,4,4"

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sink()
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Description
sink() will divert the R output to a file/connection instead of the console.
Syntax
sink(file = NULL, append = FALSE, type = c("output", "message"),
split = FALSE)
Returns
File with output
Documentation
help(sink)

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sink()
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Examples
> # example 1
> sink(file = "write.txt", append = TRUE, type = "output")
> x <- 1:5
> x * 2
> readLines("write.txt") # nothing is printed on console
> sink() # stop diverting output to file
> readLines("write.txt")
[1] "[1] 2 4 6 8 10"
[2] "[1] "[1] 2 4 6 8 10""
[3] "[1] 2 4 6 8 10"
[4] "[1] "[1] 2 4 6 8 10" "[1] "[1] 2 4 6 8 10"""
[5] "[3] "[1] 2 4 6 8 10" "

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sink()
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Examples
> # example 2
> sink("example.txt") # start writing to example.txt file
> x <- sample(1:10)
> y <- sample(1:10)
> cat("===============================n")
> cat(" T-test between x and y n")
> cat("===============================n")
> t.test(x, y)
> sink() # stop writing to the file
> readLines("example.txt")
[1] " [1] 2 5 4 6 9 3 10 1 7 8"
[2] " [1] 6 10 5 1 4 2 9 7 3 8"
[3] "==============================="
[4] " T-test between x and y "
[5] "==============================="
[6] ""
[7] "tWelch Two Sample t-test"
[8] ""
[9] "data: x and y"
[10] "t = 0, df = 18, p-value = 1"
[11] "alternative hypothesis: true difference in means is not equal to 0"
[12] "95 percent confidence interval:"
[13] " -2.844662 2.844662"
[14] "sample estimates:"
[15] "mean of x mean of y "
[16] " 5.5 5.5 "
[17] ""

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dump()
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Description
dump() takes a vector of names of R objects and produces text representation of objects
on a file.
Syntax
dump(list, file = "dumpdata.R", append = FALSE,
control = "all", envir = parent.frame(), evaluate = TRUE)
Returns
R file with text representation of R objects
Documentation
help(dump)

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dump()
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Examples
> # example 1
> x <- sample(1:10)
> y <- sample(1:10)
> xy <- list(x = x, y = y) # create a list
> dump("xy", file = "dump.Rdmped") # write xy to dump.R file
> unlink("dump.R") # close connection to dump.R file
> rm("x", "y", "xy") # remove objects x, y and xy from the workspace
> x # x is not available in the workspace
Error: object 'x' not found
> source("dump.Rdmped") # source dump.R file
> xy
$x
[1] 6 4 9 10 2 8 5 3 7 1
$y
[1] 8 7 6 9 3 1 5 2 4 10

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save()
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Description
save() writes an external representation of the R objects to specified file.
Syntax
save(R object, file_name)
Returns/Creates
R file with external representation of R objects
Documentation
help(save)

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save()
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Examples
> # example 1
> # save the following data in a R data file
> x <- 1:10
> save(x, file = "x.RData")
> # remove x from the workspace
> rm(x)
> # load x into workspace
> load("x.RData") # we will look at this function in a file
> # view the data
> x
[1] 1 2 3 4 5 6 7 8 9 10

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Next Steps...
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In the next unit, we will learn to transform/reshape data in R:
● Reorder Data
● Subset/Filter Data
● Combine Data
● Transform Data

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Connect With Us
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● Data Visualization
● Web Applications
● Package Development
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