SQL-style pattern-matching operators

Convenience operators for regular-expression matching, inspired by SQL's LIKE. Each takes a character vector x and a single pattern, and returns a logical vector the same length as x.

%rlike% matches case-insensitively, equivalent to grepl(pattern, x, ignore.case = TRUE).

%perl% matches case-sensitively using Perl-compatible regular expressions, equivalent to grepl(pattern, x, perl = TRUE).

Usage

x %rlike% pattern

x %perl% pattern

Arguments

x

a character vector

pattern

a single character expression (regular expression)

Value

A logical vector the same length as x.

Note

If you are working with data.table, prefer its own (faster) %like% operator.

Author

Ben Wiseman, benjamin.h.wiseman@gmail.com

Examples

x <- c("foo", "bar", "dOe", "rei", "mei", "obo")

# case-insensitive: where x contains an "o" (any case)
x[x %rlike% "O"]
#> [1] "foo" "dOe" "obo"
# [1] "foo" "dOe" "obo"

# case-sensitive Perl matching: middle letter is an upper-case "O"
x[x %perl% "[a-z]O[a-z]"]
#> [1] "dOe"
# [1] "dOe"