topchef topchef - 4 months ago 52
R Question

Checking if string is in uppercase in R

Is there simpler method to match regex pattern in its entirety? For example, to check if given string is uppercase the following 2 methods but seem too complex. Checking stringr I found no indication for simpler solution either.

Method 1:

isUpperMethod1 <- function(s) {
return (all(grepl("[[:upper:]]", strsplit(s, "")[[1]])))

Method 2:

isUpperMethod2 <- function(s) {
m = regexpr("[[:upper:]]+", s)
return (regmatches(s, m) == s)

I intentionally omit handling of empty, NA, NULL strings to avoid bloated code.

The uppercase pattern can be generalized to arbitrarily regex pattern (or character set).

I see no problems with both solutions above except that they seem excessively complex for the problem solved.


You can use the ^ and $ patterns to match the beginning and end of the string

grepl("^[[:upper:]]+$", s)