glob2rx {utils} | R Documentation |
Change wildcard aka globbing patterns into the
corresponding regular expressions (regexp
).
glob2rx(pattern, trim.head = FALSE, trim.tail = TRUE)
pattern |
character vector |
trim.head |
logical specifying if leading |
trim.tail |
logical specifying if trailing |
This takes a wildcard as used by most shells and returns an equivalent
regular expression. ?
is mapped to .
(match a single
character), *
to .*
(match any string, including an
empty one), and the pattern is anchored (it must start at the
beginning and end at the end). Optionally, the resulting regexp is
simplified.
Note that now even (
, [
and {
can be used
in pattern
, but glob2rx()
may not work correctly with
arbitrary characters in pattern
.
A character vector of the same length as the input pattern
where each wildcard is translated to the corresponding
regular expression.
Martin Maechler, Unix/sed based version, 1991; current: 2004
regexp
about regular expression,
sub
, etc about substitutions using regexps.
stopifnot(glob2rx("abc.*") == "^abc\\.",
glob2rx("a?b.*") == "^a.b\\.",
glob2rx("a?b.*", trim.tail = FALSE) == "^a.b\\..*$",
glob2rx("*.doc") == "^.*\\.doc$",
glob2rx("*.doc", trim.head = TRUE) == "\\.doc$",
glob2rx("*.t*") == "^.*\\.t",
glob2rx("*.t??") == "^.*\\.t..$",
glob2rx("*[*") == "^.*\\["
)