R: Count the Number of Pattern Matches

stri_count {stringi} | R Documentation

## Count the Number of Pattern Matches

### Description

These functions count the number of occurrences of a pattern in a string.

### Usage

    stri_count(str, ..., regex, fixed, coll, charclass)

    stri_count_charclass(str, pattern)

    stri_count_coll(str, pattern, ..., opts_collator = NULL)

    stri_count_fixed(str, pattern, ..., opts_fixed = NULL)

    stri_count_regex(str, pattern, ..., opts_regex = NULL)

### Arguments

`str` | character vector; strings to search in
`...` | supplementary arguments passed to the underlying functions, including additional settings for `opts_collator`, `opts_regex`, `opts_fixed`, and so on
`pattern, regex, fixed, coll, charclass` | character vector; search patterns; for more details refer to stringi-search
`opts_collator, opts_fixed, opts_regex` | a named list used to tune up the search engine's settings; see `stri_opts_collator`, `stri_opts_fixed`, and `stri_opts_regex`, respectively; `NULL` for the defaults

### Details

Vectorized over `str` and `pattern` (with recycling of the elements in the shorter vector if necessary). This allows to, for instance, search for one pattern in each given string, search for each pattern in one given string, and search for the i-th pattern within the i-th string.

If `pattern` is empty, then the result is `NA` and a warning is generated.

`stri_count` is a convenience function. It calls either `stri_count_regex`, `stri_count_fixed`, `stri_count_coll`, or `stri_count_charclass`, depending on the argument used.

### Value

All the functions return an integer vector.

### See Also

Other search_count: `stri_count_boundaries()`, `stringi-search`

### Examples

    s <- "Lorem ipsum dolor sit amet, consectetur adipisicing elit."
    stri_count(s, fixed="dolor")
    stri_count(s, regex="\\p{L}+")

    stri_count_fixed(s, " ")
    stri_count_fixed(s, "o")
    stri_count_fixed(s, "it")
    stri_count_fixed(s, letters)
    stri_count_fixed("babab", "b")
    stri_count_fixed(c("stringi", "123"), "string")

    stri_count_charclass(c("stRRRingi", "STrrrINGI", "123"),
       c("\\p{Ll}", "\\p{Lu}", "\\p{Zs}"))
    stri_count_charclass(" \t\n", "\\p{WHITE_SPACE}") # white space - binary property
    stri_count_charclass(" \t\n", "\\p{Z}") # white-space - general category (note the difference)

    stri_count_regex(s, "(s|el)it")
    stri_count_regex(s, "i.i")
    stri_count_regex(s, ".it")
    stri_count_regex("bab baab baaab", c("b.*?b", "b.b"))
    stri_count_regex(c("stringi", "123"), "^(s|1)")

[Package stringi version 1.4.6 Index]