如何仅过滤包含 R 中所有字符串中的所有大写字母的向量

Question

I need to filter rows that are uppercase in R. I managed to use the following code:

filter(str_detect(fruit, "^[:upper:]+$"))

However, some of the values of the column "fruit" contain two or three strings, and the code above only works for the cases when there is only one string. I can't share the data, but this example works for my purposes (only the str_detect part)

fruit <- c("apple", "ORANGE", "kiwi" ,"TWO PEARS", "A BIG PINEAPPLE", "LEMON")
str_detect(fruit, "^[:upper:]+$")
[1] FALSE  TRUE FALSE FALSE FALSE  TRUE

What I want is to also be able to identify "TWO PEARS" and "A BIG PINEAPPLE". Could you please help me?

Many thanks!

Answer 1

Try to include the space character class.

stringr::str_detect(fruit, "^[[:upper:][:space:]]+$")
#[1] FALSE  TRUE FALSE  TRUE  TRUE  TRUE

Following the comment to the question, negate uppercase:

stringr::str_detect(fruit, "^[^[:lower:]]+$")
#[1] FALSE  TRUE FALSE  TRUE  TRUE  TRUE

Answer 2

We can use grep in base R

grep("^[A-Z ]+$", fruit, value = TRUE)
#[1] "ORANGE"          "TWO PEARS"       "A BIG PINEAPPLE" "LEMON"   

To get the other elements

grep("^[A-Z ]+$", fruit, value = TRUE, inverse = TRUE)