1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
|
% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/subset.R
\name{str_which}
\alias{str_which}
\title{Find matching indices}
\usage{
str_which(string, pattern, negate = FALSE)
}
\arguments{
\item{string}{Input vector. Either a character vector, or something
coercible to one.}
\item{pattern}{Pattern to look for.
The default interpretation is a regular expression, as described in
\code{vignette("regular-expressions")}. Use \code{\link[=regex]{regex()}} for finer control of the
matching behaviour.
Match a fixed string (i.e. by comparing only bytes), using
\code{\link[=fixed]{fixed()}}. This is fast, but approximate. Generally,
for matching human text, you'll want \code{\link[=coll]{coll()}} which
respects character matching rules for the specified locale.
Match character, word, line and sentence boundaries with
\code{\link[=boundary]{boundary()}}. An empty pattern, "", is equivalent to
\code{boundary("character")}.}
\item{negate}{If \code{TRUE}, inverts the resulting boolean vector.}
}
\value{
An integer vector, usually smaller than \code{string}.
}
\description{
\code{str_which()} returns the indices of \code{string} where there's at least
one match to \code{pattern}. It's a wrapper around
\code{which(str_detect(x, pattern))}, and is equivalent to \code{grep(pattern, x)}.
}
\examples{
fruit <- c("apple", "banana", "pear", "pineapple")
str_which(fruit, "a")
# Elements that don't match
str_which(fruit, "^p", negate = TRUE)
# Missings never match
str_which(c("a", NA, "b"), ".")
}
|
