You can use the following basic syntax with the grepl() function in R to filter for rows in a data frame that contain one of several string patterns in a specific column:
library(dplyr) new_df <- filter(df, grepl(paste(my_patterns, collapse='|'), my_column))
This particular syntax filters the data frame for rows where the value in the column called my_column contains one of the string patterns in the vector called my_patterns.
The following example shows how to use this syntax in practice.
Example: How to Use grepl() with Multiple Patterns in R
Suppose we have the following data frame in R that contains information about various basketball teams:
#create data frame df <- data.frame(team=c('Mavs', 'Hawks', 'Nets', 'Heat', 'Cavs'), points=c(104, 115, 124, 120, 112), status=c('Bad', 'Good', 'Excellent', 'Great', 'Bad')) #view data frame df team points status 1 Mavs 104 Bad 2 Hawks 115 Good 3 Nets 124 Excellent 4 Heat 120 Great 5 Cavs 112 Bad
Suppose we would like to filter the data frame to only contain rows where the string in the status column contains one of the following string patterns:
We can use the following syntax with the grepl() function to do so:
library(dplyr) #define patterns to search for my_patterns <- c('Good', 'Gre', 'Ex') #filter for rows where status column contains one of several strings new_df <- filter(df, grepl(paste(my_patterns, collapse='|'), status)) #view results new_df team points status 1 Hawks 115 Good 2 Nets 124 Excellent 3 Heat 120 Great
Notice that the data frame has been filtered to only contain the rows where the string in the status column contains one of the three patterns that we specified.
Note that by using the paste() function with the argument collapse=’|’ we actually searched for the string ‘Good|Gre|Ex’ in the status column.
Since the | symbol in R stands for “OR” we were able to search for rows that contained ‘Good’ or Gre’ or ‘Ex’ in the status column.
The following tutorials explain how to perform other common tasks in R:
How to Mutate Variable if Column Contains String Using dplyr
How to Remove First Character from Strings Using dplyr
How to Replace String in Column Using dplyr