str_subset() returns all elements of string where there's at least
one match to pattern. It's a wrapper around x[str_detect(x, pattern)],
and is equivalent to grep(pattern, x, value = TRUE).
Use str_extract() to find the location of the match within each string.
str_subset(string, pattern, negate = FALSE)Input vector. Either a character vector, or something coercible to one.
Pattern to look for.
The default interpretation is a regular expression, as described in
vignette("regular-expressions"). Use regex() for finer control of the
matching behaviour.
Match a fixed string (i.e. by comparing only bytes), using
fixed(). This is fast, but approximate. Generally,
for matching human text, you'll want coll() which
respects character matching rules for the specified locale.
Match character, word, line and sentence boundaries with
boundary(). An empty pattern, "", is equivalent to
boundary("character").
If TRUE, inverts the resulting boolean vector.
A character vector, usually smaller than string.
grep() with argument value = TRUE,
stringi::stri_subset() for the underlying implementation.
fruit <- c("apple", "banana", "pear", "pineapple")
str_subset(fruit, "a")
#> [1] "apple" "banana" "pear" "pineapple"
str_subset(fruit, "^a")
#> [1] "apple"
str_subset(fruit, "a$")
#> [1] "banana"
str_subset(fruit, "b")
#> [1] "banana"
str_subset(fruit, "[aeiou]")
#> [1] "apple" "banana" "pear" "pineapple"
# Elements that don't match
str_subset(fruit, "^p", negate = TRUE)
#> [1] "apple" "banana"
# Missings never match
str_subset(c("a", NA, "b"), ".")
#> [1] "a" "b"