| pattern {operators} | R Documentation |
Set of convenience functions to handle strings and pattern matching.
These are basically
companion binary operators for the classic R function
grep and regexpr.
x %~% rx x %!~% rx x %~*% rx x %!~*% rx x %~+% rx x %!~+% rx
x |
text to manipulate |
rx |
regular expression |
%~% : gives a logical vector indicating which elements of x
match the regular expression rx. %!~% is the negation of
%~%
%~*% : gives a single logical indicating if all the elements
of x are matching the regular expression rx. %!~*% is the
negation of %~*%.
%~+% : gives a single logical indicating if any
element of x matches the regular expression rx. %!~+%
is the negation of %~+%.
The matching is done using a modified version of the
regexpr function.
The modification is performed by applying the
operators.regexpr option to the regexpr function
via the %but% operator.
The default version of regexpr enables the perl and
extended options. See %but% for details.
Romain Francois <francoisromain@free.fr>
grep, gsub, %~|% for regular expression filters
txt <- c("arm","foot","lefroo", "bafoobar")
txt %~% "foo"
txt %!~% "foo"
txt %~*% "foo"
txt %~+% "foo"
txt %!~*% "foo"
txt %!~+% "foo"
txt %~% "[a-z]"
txt %!~% "[a-z]"
txt %~*% "[a-z]"
txt %~+% "[a-z]"
txt %!~*% "[a-z]"
txt %!~+% "[a-z]"
cols <- colors()
cols[ cols %~% "^blue" ]
# see also %~|%
## needs perl regular expression for the \\d, see
with( options( operators.regexpr = "p" ), {
cols[ cols %!~% "\d$" ]
} )