check if a string contains only alphanumeric characters in R

 is_alpha_num <- function(x) {
   all(grepl("^[A-Za-z0-9]+$", x))
 }

This code checks if a string contains only alphanumeric characters. First, the variable ‘is_alpha_num’ defines a function with the variable ‘x’. Then, ‘all’ provides a boolean value based on whether or not all elements within ‘x’ meet the criteria specified by the ‘grepl’ function. The ‘grepl’ function checks if the given string matches the regular expression ’^[A-Za-z0-9]+$‘. This expression checks for any combination of alphanumeric characters from A-Z, a-z, and 0-9. If the string meets this criteria, the ‘all’ function will return a value of TRUE, and FALSE otherwise.