r mask for grep for finding the repeated words

Question

I just want find rows with the repeated word HALL (more than one time). For example, "HALL #1 HALL #2 HALL #3". I tried to use

grepl("HALL{2,}", "HALL #1 HALL #2 HALL #3")

but grepl returned FALSE. What am I doing wrong?

Answer 1

You can use stringr,

str_count("HALL #1 HALL #2 HALL #3", 'HALL')>1
#[1] TRUE

Answer 2

You could use (?:.*?HALL.*?){2,}:

grepl("(?:.*?HALL.*?){2,}", "HALL #1 HALL #2 HALL #3")
#[1] TRUE

Here is a breakdown of the above regex.