Remove Characters Before or After Point in String in R (Example)

This article shows how to delete characters in a character string before or after a point in the R programming language.

The page is structured as follows:

1) Creation of Example Data

2) Example 1: Remove Part After . Using gsub() Function and \\

3) Example 2: Remove Part Before . Using gsub() Function and \\

4) Video, Further Resources & Summary

Let’s start right away!

Creation of Example Data

The following data will be used as basement for this R tutorial:

x <- "aaaa.bbbbbb"          # Create example data
x                           # Print example data
# [1] "aaaa.bbbbbb"

The previous output of the RStudio console shows the structure of the example data – It’s a single character string containing the letters a and b and a point or dot (i.e. “.”) in the middle.

Example 1: Remove Part After . Using gsub() Function and \\

This example explains how to extract only the part of a character string before or after a point.

Let’s first apply the gsub function as we usually would, in case we want to remove the part of a string before or after a pattern:

gsub("..*", "", x)          # Apply gsub without \\
# [1] ""

As you can see, the RStudio console returns an empty character after running the previous R code.

The reason for this is that the symbol . is considered as a special character. For that reason, we have to use a double backslash in front of the point (i.e. \\).

gsub("\\..*", "", x)        # Apply gsub with \\
# [1] "aaaa"

This works as expected!

Example 2: Remove Part Before . Using gsub() Function and \\

It is also possible to remove all characters in front of a point using the gsub function.

For this task, we can use the R code below:

gsub(".*\\.", "", x)        # Apply gsub with \\
# [1] "bbbbbb"

Looks good!

Video, Further Resources & Summary

In case you need more info on the R programming codes of this article, you may watch the following video which I have published on my YouTube channel. In the video, I’m explaining the R programming code of this article.

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Besides the video, you may want to have a look at the other tutorials of this homepage. I have released numerous tutorials already:

Summary: In this tutorial, I have explained how to remove characters before or after points in the R programming language. Let me know in the comments, if you have additional questions.

6 Comments. Leave new

Girsão
July 13, 2021 7:37 pm

You forgot to tell us how to remove the characters before a point.

Reply
- Joachim
  August 2, 2021 9:58 am
  
  Hey Girsão,
  
  Thanks a lot for the hint, it seems like I have forgotten to do this when I created the tutorial.
  
  I have just added another example, which explains how to delete all characters before a point.
  
  Regards
  
  Joachim
  
  Reply
ad
May 3, 2022 8:06 am

what if data is aaa.bbbb.cccc, and want to extract bbbb?

Reply
- Joachim
  May 3, 2022 1:19 pm
  Hey,
  
  This is probably not the most efficient solution, but it should work:
  substr("aaa.bbbb.cccc", gregexpr(".", "aaa.bbbb.cccc")[[1]][1] + 1, gregexpr(".", "aaa.bbbb.cccc")[[1]][2] - 1)
  substr("aaa.bbbb.cccc", gregexpr(".", "aaa.bbbb.cccc")[[1]][1] + 1, gregexpr(".", "aaa.bbbb.cccc")[[1]][2] - 1)
  Regards,
  Joachim
  Reply
Nadal
January 23, 2023 3:26 pm

hi dear .. your classes are amazing .
if i have the below data frame ,,, how can i run the same command to remove FY from the Year column ? thank you

Identifier Company Name Country Year
ELSE.OQ Electro-Sensors Inc USA FY2021
ELSE.OQ Electro-Sensors Inc USA FY2020
ELSE.OQ Electro-Sensors Inc USA FY2019
ELSE.OQ Electro-Sensors Inc USA FY2018
ELSE.OQ Electro-Sensors Inc USA FY2017
ELSE.OQ Electro-Sensors Inc USA FY2016
ELSE.OQ Electro-Sensors Inc USA FY2015
ELSE.OQ Electro-Sensors Inc USA FY2014
ELSE.OQ Electro-Sensors Inc USA FY2013
ELSE.OQ Electro-Sensors Inc USA FY2012
ELSE.OQ Electro-Sensors Inc USA FY2011
ELSE.OQ Electro-Sensors Inc USA FY2010
ELSE.OQ Electro-Sensors Inc USA FY2009
ELSE.OQ Electro-Sensors Inc USA FY2008
ELSE.OQ Electro-Sensors Inc USA FY2007
ELSE.OQ Electro-Sensors Inc USA FY2006
ELSE.OQ Electro-Sensors Inc USA FY2005
ELSE.OQ Electro-Sensors Inc USA FY2004
ELSE.OQ Electro-Sensors Inc USA FY2003

Reply
- Cansu (Statistics Globe)
  January 23, 2023 3:39 pm
  Hey Nadal,
  Thank you for such a nice feedback. You can check the code below.
  data<-data.frame(Year= c("FY2021","FY2020","FY2022")) data # Year # 1 FY2021 # 2 FY2020 # 3 FY2022 data$Year<-gsub("FY", "", data$Year) data # Year # 1 2021 # 2 2020 # 3 2022
  data<-data.frame(Year= c("FY2021","FY2020","FY2022")) data # Year # 1 FY2021 # 2 FY2020 # 3 FY2022 data$Year<-gsub("FY", "", data$Year) data # Year # 1 2021 # 2 2020 # 3 2022
  For more detailed information, you can check our tutorial, Replace Specific Characters in String in R.
  
  Regards,
  Cansu
  Reply