The cat() function in R can be used to concatenate together several objects in R.

This function uses the following basic syntax:

cat(..., file = "", sep = " ", append = FALSE))

where:

• …: Objects to concatenate
• file: File name to send output to
• sep: Separator to use between objects
• append: Whether to append output to existing file or create new file

The following examples show how to use this function in different ways.

Example 1: Use cat() to Concatenate Objects

We can use the cat() function to concatenate three strings in R:

#concatenate three strings
cat("hey", "there", "everyone")

hey there everyone

The three strings are concatenated together, with each string separated by a space.

Example 2: Use cat() to Concatenate Objects with Custom Separator

We can use the cat() function to concatenate three strings in R, using a dash as the separator:

#concatenate three strings, using dash as separator
cat("hey", "there", "everyone", sep="-")

hey-there-everyone

Or we could use “n” as the separator, which species that each string should be separated by a new line:

#concatenate three strings, using new line as separator
cat("hey", "there", "everyone", sep="n")

hey
there
everyone

Example 3: Use cat() to Concatenate Objects and Output Results to File

We can use the cat() function to concatenate three strings in R and output the results to a text file:

#concatenate three strings and output results to txt file
cat("hey", "there", "everyone", sep="n", file="my_data.txt")

I can then navigate to my and view the contents of this text file:

We could also output the results to a CSV file:

#concatenate three strings and output results to CSV file
cat("hey", "there", "everyone", sep="n", file="my_data.csv")

I can then navigate to my and view the contents of this text file:

Example 4: Use cat() to Concatenate Objects and Append Results to File

We can use the cat() function to concatenate three strings in R and append the results to an existing CSV file:

#concatenate three strings and output results to CSV file
cat("hey", "there", "everyone", sep="n", file="my_data.csv")

#append results of this concatenation to first file
cat("how", "are", "you", sep="n", file="my_data.csv", append=TRUE)

I can then navigate to my and view the contents of this CSV file:

Notice that the results of the second cat() function have been appended to the file created by the first cat() function.

Additional Resources