R How to Match Globbing Pattern & Character String (4 Examples)
In this article you’ll learn how to perform matching with globbing or wildcard patterns in the R programming language.
Constructing Example Data
wc <- "AAA*" # Wildcard string vec <- c("AAAy", "BBBx", "AAA5", "xyz") # Character string vector |
wc <- "AAA*" # Wildcard string vec <- c("AAAy", "BBBx", "AAA5", "xyz") # Character string vector
Example 1: Get Position of Matching Wildcard Pattern
grep(wc, vec) # Apply grep() function # [1] 1 3 |
grep(wc, vec) # Apply grep() function # [1] 1 3
Example 2: Get Character Strings that Match Wildcard Pattern
grep(wc, vec, value = TRUE) # Apply grep() function & value argument # [1] "AAAy" "AAA5" |
grep(wc, vec, value = TRUE) # Apply grep() function & value argument # [1] "AAAy" "AAA5"
Example 3: Get Logical Values Corresponding to Matching Wildcard Pattern
grepl(wc, vec) # Apply grepl() # [1] TRUE FALSE TRUE FALSE |
grepl(wc, vec) # Apply grepl() # [1] TRUE FALSE TRUE FALSE
Example 4: Create Data Subset of Elements that Match Wildcard Pattern
vec_subset <- vec[grepl(wc, vec)] # Create vector subset vec_subset # Print subset # [1] "AAAy" "AAA5" |
vec_subset <- vec[grepl(wc, vec)] # Create vector subset vec_subset # Print subset # [1] "AAAy" "AAA5"
Related Articles & Further Resources
Have a look at the following R programming language tutorials. They explain topics such as data conversion, character strings, and extracting data: