Test a pattern in strings, and return boolean.

Usage

re2_detect(string, pattern, anchor = UNANCHORED, parallel = FALSE, grain_size = 1e+05, ...)

Arguments

string

a character vector

pattern

a character vector or pre-compiled regular expressions

anchor

see UNANCHORED

parallel

use multithread

grain_size

a minimum chunk size for tuning the behavior of parallel algorithms

...

further arguments passed to re2

Examples

re2_detect("one", "(o.e)")

[1] TRUE

re2_detect("123-234-2222", "\\d\\d\\d-\\d\\d\\d-\\d\\d\\d\\d")

[1] TRUE


words = c("sunny","beach","happy","really")
re2_detect(words, "y")

[1]  TRUE FALSE  TRUE  TRUE

re2_detect(words, "^b")

[1] FALSE  TRUE FALSE FALSE

re2_detect(words, "[abc]")

[1] FALSE  TRUE  TRUE  TRUE


# vectorize
(res = re2_detect("This", letters))

 [1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE  TRUE  TRUE FALSE FALSE FALSE
[13] FALSE FALSE FALSE FALSE FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE
[25] FALSE FALSE

letters[res]

[1] "h" "i" "s"


letters[re2_detect("This", letters, case_sensitive = FALSE)]

[1] "h" "i" "s" "t"


letters[re2_detect("This", re2(letters, case_sensitive = FALSE))]

[1] "h" "i" "s" "t"


# In stringi, "" empty search patterns return NA.
# In re2r, empty search patterns will match
# empty string.

re2_detect("abc", "")

[1] TRUE

stringi::stri_detect("abc", regex = "")

Warning message:
empty search patterns are not supported
[1] NA