stri_subset: Select Elements that Match a Given Pattern

Description

These functions return or modify a subvector consisting of strings that match a given pattern. In other words, they are roughly equivalent (but faster and easier to use) to a call to str[stri_detect(str, ...)] or str[stri_detect(str, ...)] <- value.

Usage

stri_subset(str, ..., regex, fixed, coll, charclass)
stri_subset(str, ..., regex, fixed, coll, charclass) <- value
stri_subset_fixed(str, pattern, omit_na = FALSE, negate = FALSE, ...,
  opts_fixed = NULL)
stri_subset_fixed(str, pattern, negate=FALSE, ..., opts_fixed=NULL) <- value
stri_subset_charclass(str, pattern, omit_na = FALSE, negate = FALSE)
stri_subset_charclass(str, pattern, negate=FALSE) <- value
stri_subset_coll(str, pattern, omit_na = FALSE, negate = FALSE, ...,
  opts_collator = NULL)
stri_subset_coll(str, pattern, negate=FALSE, ..., opts_collator=NULL) <- value
stri_subset_regex(str, pattern, omit_na = FALSE, negate = FALSE, ...,
  opts_regex = NULL)
stri_subset_regex(str, pattern, negate=FALSE, ..., opts_regex=NULL) <- value

Arguments

str

character vector with strings to search in

...

supplementary arguments passed to the underlying functions, including additional settings for opts_collator, opts_regex, opts_fixed, and so on

value

character vector to be substituted with; replacement function only

pattern, regex, fixed, coll, charclass

character vector defining search patterns; for more details refer to stringi-search; the replacement functions accept only one pattern at a time

omit_na

single logical value; should missing values be excluded from the result?

negate

single logical value; whether a no-match is rather of interest

opts_collator, opts_fixed, opts_regex

a named list used to tune up a search engine's settings; see stri_opts_collator, stri_opts_fixed, and stri_opts_regex, respectively; NULL for default settings;

Value

The stri_subset functions return a character vector. As usual, the output encoding is always UTF-8.

The stri_subset<- functions change the str object.

Details

Vectorized over str, and pattern or value (replacement version).

stri_subset and stri_subset<- are convenience functions. They call either stri_subset_regex, stri_subset_fixed, stri_subset_coll, or stri_subset_charclass, depending on the argument used. Relying on these underlying functions will make your code run slightly faster.

Examples

Run this code

# NOT RUN {
stri_subset_regex(c("stringi R", "123", "ID456", ""), "^[0-9]+$")

x <- c("stringi R", "123", "ID456", "")
stri_subset_regex(x, "[^0-9]+|^$") <- NA
print(x)

x <- c("stringi R", "123", "ID456", "")
stri_subset_regex(x, "^[0-9]+$", negate=TRUE) <- NA
print(x)

# }