grepRaw searches for substring
pattern matches within a
raw vector containing a regular expression
(or fixed pattern for
a raw vector where matches are sought, or an object which can
be coerced by
An integer specifying the offset from
which the search should start. Must be positive. The beginning of
line is defined to be at that offset so
logical. Determines the return value: see ‘Value’.
grep, seeks matching patterns within the raw
x . This has implications especially in the
TRUE case, e.g., patterns matching empty strings are inherently
infinite and thus may lead to unexpected results.
invert is interpreted as asking to return the
complement of the match, which is only meaningful for
offset determines the start of the search, not
of the complement. Note that
invert = TRUE with
TRUE will split
x into pieces delimited by the pattern
including leading and trailing empty strings (consequently the use of
regular expressions with
"$" in that case may
lead to less intuitive results).
Some combinations of arguments such as
fixed = TRUE with
value = TRUE are supported but are less meaningful.
grepRaw(value = FALSE) returns an integer vector of the offsets
at which matches have occurred. If
all = FALSE then it will be
either of length zero (no match) or length one (first matching
grepRaw(value = TRUE, all = FALSE) returns a raw vector which
is either empty (no match) or the matched part of
grepRaw(value = TRUE, all = TRUE) returns a (potentially
empty) list of raw vectors corresponding to the matched parts.
The TRE library of Ville Laurikari (http://laurikari.net/tre/)
is used except for
fixed = TRUE.
regular expression (aka
regexp) for the details
of the pattern specification.
grep for matching character vectors.
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