| vec_match {vctrs} | R Documentation |
vec_in() returns a logical vector based on whether needle is found in
haystack. vec_match() returns an integer vector giving location of
needle in haystack, or NA if it's not found.
vec_match(needles, haystack) vec_in(needles, haystack)
needles, haystack |
Vector of
|
vec_in() is equivalent to %in%; vec_match() is equivalen to match().
A vector the same length as needles. vec_in() returns a
logical vector; vec_match() returns an integer vector.
In most cases, missing values are not considered to be equal, i.e.
NA == NA is not TRUE. This behaviour would be unappealing here,
so these functions consider all NAs to be equal. (Similarly,
all NaN are also considered to be equal.)
These functions are currently slightly slower than their base equivalents. This is primarily because they do a little more checking and coercion in R, which makes them both a litter safer and more generic. Additionally, the C code underlying vctrs has not yet been implemented: we expect some performance improvements when that happens.
hadley <- strsplit("hadley", "")[[1]]
vec_match(hadley, letters)
vowels <- c("a", "e", "i", "o", "u")
vec_match(hadley, vowels)
vec_in(hadley, vowels)
# Only the first index of duplicates is returned
vec_match(c("a", "b"), c("a", "b", "a", "b"))