Exporting Data from scripts in R Programming

Exporting Data in detail

When a program terminates, all data held in the program is lost. To ensure data persistence, we store the fetched information in files. This enables transferring data across systems and prevents re-entering large datasets. Files can be stored in formats such as .txt, .csv, or even in online/cloud storage. R provides straightforward methods to export data to these file types.

Exporting Data to a Text File

Text files are a common format for data storage. R provides methods like write.table() to export data frames or matrices to text files.

1. write.table(): The write.table() function writes a data frame or matrix to a text file.

Syntax:

write.table(x, file, append = FALSE, sep = " ", dec = ".", row.names = TRUE, col.names = TRUE)

Parameters:

• x: Data frame or matrix to be written.
• file: File name as a string.
• sep: Field separator (e.g., \t for tab-separated values).
• dec: Decimal separator (default is .).
• row.names: Logical or character vector for row names.
• col.names: Logical or character vector for column names.

Example:

# Creating a data frame
employee_data <- data.frame(
  "Employee" = c("John", "Emma", "Liam"),
  "Department" = c("HR", "IT", "Finance"),
  "Age" = c(29, 34, 41)
)

# Exporting the data frame to a text file
write.table(employee_data,
            file = "employee_data.txt",
            sep = "\t",
            row.names = TRUE,
            col.names = NA)

Output:

""    "Employee"    "Department"    "Age"
"1"    "John"        "HR"             29
"2"    "Emma"        "IT"             34
"3"    "Liam"        "Finance"        41

write_tsv(): The write_tsv() method from the readr package exports tab-separated values.

Syntax:

write_tsv(file, path)

Example:

# Creating a data frame
employee_data <- data.frame(
  "Employee" = c("John", "Emma", "Liam"),
  "Department" = c("HR", "IT", "Finance"),
  "Age" = c(29, 34, 41)
)

# Exporting the data frame to a text file
write.table(employee_data,
            file = "employee_data.txt",
            sep = "\t",
            row.names = TRUE,
            col.names = NA)

Output:

""    "Employee"    "Department"    "Age"
"1"    "John"        "HR"             29
"2"    "Emma"        "IT"             34
"3"    "Liam"        "Finance"        41

write_tsv(): The write_tsv() method from the readr package exports tab-separated values.

Syntax:

write_tsv(file, path)

Example:

# Importing the readr package
library(readr)

# Creating a data frame
student_data <- data.frame(
  "Name" = c("Alice", "Bob", "Charlie"),
  "Grade" = c("A", "B", "A+"),
  "Age" = c(20, 22, 21)
)

# Exporting the data frame using write_tsv()
write_tsv(student_data, path = "student_data.txt")

Output:

Name    Grade    Age
Alice   A        20
Bob     B        22
Charlie A+       21

Exporting Data to a CSV File

CSV files are widely used for storing tabular data. R provides multiple methods for exporting data to .csv files.

write.table(): The write.table() function can also export data to CSV files by specifying sep = ",".

Example:

# Creating a data frame
product_data <- data.frame(
  "Product" = c("Laptop", "Phone", "Tablet"),
  "Price" = c(1000, 500, 300),
  "Stock" = c(50, 200, 150)
)

# Exporting the data frame to a CSV file
write.table(product_data,
            file = "product_data.csv",
            sep = ",",
            row.names = FALSE)

Output:

Product,Price,Stock
Laptop,1000,50
Phone,500,200
Tablet,300,150

write.csv()

The write.csv() function simplifies exporting data to CSV files, using a comma as the default separator.

Example:

# Creating a data frame
city_data <- data.frame(
  "City" = c("New York", "Los Angeles", "Chicago"),
  "Population" = c(8419600, 3980400, 2716000),
  "Area" = c(468.9, 503, 227.3)
)

# Exporting the data frame to a CSV file
write.csv(city_data, file = "city_data.csv")

Output:

"","City","Population","Area"
"1","New York",8419600,468.9
"2","Los Angeles",3980400,503
"3","Chicago",2716000,227.3

write.csv2():The write.csv2() function is similar to write.csv() but uses a semicolon (;) as the separator and a comma for the decimal point.

Example:

# Creating a data frame
sales_data <- data.frame(
  "Month" = c("January", "February", "March"),
  "Sales" = c(15000.50, 17000.75, 16000.30)
)

# Exporting the data frame to a CSV file
write.csv2(sales_data, file = "sales_data.csv")

Output:

";""Month"";""Sales"
"1";"January";"15000,50"
"2";"February";"17000,75"
"3";"March";"16000,30"

write_csv(): The write_csv() method from the readr package exports data to CSV files.

Example:

# Importing the readr package
library(readr)

# Creating a data frame
book_data <- data.frame(
  "Title" = c("R for Data Science", "Python Crash Course", "The Art of R Programming"),
  "Author" = c("Hadley Wickham", "Eric Matthes", "Norman Matloff"),
  "Price" = c(35.99, 29.99, 45.00)
)

# Exporting the data frame using write_csv()
write_csv(book_data, path = "book_data.csv")

Output:

Title,Author,Price
R for Data Science,Hadley Wickham,35.99
Python Crash Course,Eric Matthes,29.99
The Art of R Programming,Norman Matloff,45.00