chr.grep: Multiple Pattern Matching

In misty: Miscellaneous Functions 'T. Yanagida'

Multiple Pattern Matching

Description

This function searches for matches to the character vector specified in pattern within each element of the character vector x.

Usage

chr.grep(pattern, x, ignore.case = FALSE, perl = FALSE, value = FALSE,
         fixed = FALSE, useBytes = FALSE, invert = FALSE, check = TRUE)

chr.grepl(pattern, x, ignore.case = FALSE, perl = FALSE, fixed = FALSE,
          useBytes = FALSE, check = TRUE)

Arguments

pattern	a character vector with character strings to be matched.
x	a character vector where matches are sought.
ignore.case	logical: if FALSE (default), the pattern matching is case sensitive and if TRUE, case is ignored during matching.
perl	logical: if TRUE Perl-compatible regexps are used.
value	logical: if FALSE (default), a vector containing the (integer) indices of the matches determined by grep is returned, and if TRUE, a vector containing the matching elements themselves is returned.
fixed	logical: if TRUE, pattern is a string to be matched as is. Overrides all conflicting arguments.
useBytes	logical: if TRUE, the matching is done byte-by-byte rather than character-by-character. See 'Details'.
invert	logical: if TRUE, function returns indices or values for elements that do not match.
check	logical: if TRUE (default), argument specification is checked.

Value

Returns a integer vector with the indices of the mathces when value = FALSE, character vector containing the matching elements when value = TRUE, or a logical vector when using the chr.grepl function.

Author(s)

Takuya Yanagida

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole

See Also

chr.gsub, chr.omit, chr.trim

Examples

chr.vector <- c("James", "Mary", "Michael", "Patricia", "Robert", "Jennifer")

# Example 1: Indices of matching elements
chr.grep(c("am", "er"), chr.vector)

# Example 2: Values of matching elements
chr.grep(c("am", "er"), chr.vector, value = TRUE)

# Example 3: Matching element?
chr.grepl(c("am", "er"), chr.vector)

misty documentation built on Oct. 24, 2024, 5:10 p.m.