R: Count the number of matches in a string.

str_count {stringr} | R Documentation

## Count the number of matches in a string.

### Description

Vectorised over `string` and `pattern`.

### Usage

    str_count(string, pattern = "")

### Arguments

`string` | Input vector. Either a character vector, or something coercible to one.
`pattern` | Pattern to look for. The default interpretation is a regular expression, as described in stringi::stringi-search-regex. Control options with `regex()`. 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")`.

### Value

An integer vector.

### See Also

`stringi::stri_count()` which this function wraps.

`str_locate()`/`str_locate_all()` to locate position of matches

### Examples

    fruit <- c("apple", "banana", "pear", "pineapple")
    str_count(fruit, "a")
    str_count(fruit, "p")
    str_count(fruit, "e")
    str_count(fruit, c("a", "b", "p", "p"))

    str_count(c("a.", "...", ".a.a"), ".")
    str_count(c("a.", "...", ".a.a"), fixed("."))

[Package stringr version 1.3.1 Index]