str_match_named: First match from multiple subjects, three argument syntax
In namedCapture: Named Capture Regular Expressions

Description Usage Arguments Value Author(s) Examples

Extract the first match of pattern from each element of subject.vec using a named capture regular expression. This function is mostly for internal use; most users should use str_match_variable instead. Result depends on engine (either PCRE or RE2) which can be specified via the namedCapture.engine option.

1 2	str_match_named(subject.vec, pattern, type.list = NULL)

`subject.vec`	character vector of subjects.
`pattern`	named capture regular expression (character vector of length 1).
`type.list`	named list of functions to apply to captured groups, in order to create non-character (typically numeric) columns in the result.

A data.frame with one row for each subject and one column for each capture group if type.list is a list of functions. Otherwise a character matrix. If subject.vec has names then they will be used for the rownames of the returned data.frame or character matrix. Otherwise if pattern has a group named "name" then it will not be returned as a column, and will instead be used for the rownames.

Toby Dylan Hocking

chr.pos.vec <- c(
  "chr10:213,054,000-213,055,000",
  "chrM:111,000-222,000",
  "this will not match",
  NA, # neither will this.
  "chr1:110-111 chr2:220-222") # two possible matches.
chr.pos.pattern <- paste0(
  "(?P<chrom>chr.*?)",
  ":",
  "(?P<chromStart>.*?)",
  "-",
  "(?P<chromEnd>[0-9,]*)")
## Specifying a list of conversion functions means that str_match_*
## should convert the matched groups from character to whatever is
## returned by those functions.
keep.digits <- function(x)as.integer(gsub("[^0-9]", "", x))
conversion.list <- list(chromStart=keep.digits, chromEnd=keep.digits)
(match.df <- namedCapture::str_match_named(chr.pos.vec, chr.pos.pattern, conversion.list))
str(match.df)