Insert Character Pattern at Particular Position of String in R (2 Examples)

On this page, I’ll show how to insert a character pattern at a particular position of a string in the R programming language.

Table of contents:

Let’s dive right in…

Creation of Example Data

The first step is to create some exemplifying data:

my_string <- "abcdefghi"                       # Create example string
my_string                                      # Print example string
# [1] "abcdefghi"

The previous RStudio console output shows that our exemplifying data is a single character string object containing a sequence of alphabetical letters.

Example 1: Insert Character Pattern in String Using gsub() Function

In this example, I’ll explain how to use the gsub function to insert a character pattern in our example string.

Consider the following R code:

my_string_new1 <- gsub("^(.{5})(.*)$",         # Apply gsub
                       "\\1_XXX_\\2",
                       my_string)
my_string_new1                                 # Print new string
# [1] "abcde_XXX_fghi"

Have a look at the previous output of the RStudio console: We have created a new character string called my_string_new1 that contains the characters of our input data and in between the characters “_XXX_”.

The previously shown R code works fine. However, it might be a bit complicated to run this R code every time we want to put a particular character pattern into a string.

The next example therefore shows how to speed up this process.

Example 2: Insert Character Pattern in String Using Manually Defined Function

The R code below explains how to create a user-defined function that inserts a character pattern in the middle of character strings.

Let’s first create our user-defined function:

fun_insert <- function(x, pos, insert) {       # Create own function
  gsub(paste0("^(.{", pos, "})(.*)$"),
       paste0("\\1", insert, "\\2"),
       x)
}

Next, we can apply our own function:

my_string_new2 <- fun_insert(x = my_string,    # Apply own function
                             pos = 5, 
                             insert = "_YYY_")
my_string_new2                                 # Print new string
# [1] "abcde_YYY_fghi"

As you can see, we have created another character string containing our input characters and the pattern “_YYY_” in the middle of the string.

Video & Further Resources

Do you want to learn more about character string manipulation in R? Then I recommend watching the following video of my YouTube channel. I’m illustrating the R codes of this article in the video.

Furthermore, you may want to have a look at some of the other tutorials on this homepage.

• Capitalize First Letter of Each Word in Character String
• Print Character String to Newline of RStudio Console
• strsplit Function in R
• R Programming Tutorials

In summary: In this article you have learned how to insert characters at specific locations in a string in the R programming language. In case you have further comments or questions, please let me know in the comments section.