Search notes:
R function: grep(…)
grep(regexp, vec) searches for strings in the character
vector that match the
regular expression regexp and returns a vector with the matched strings.
words=c("Foo", "Bar", "Baz", "One", "Two", "Three")
# grep returns a Vector of the indices of the matched elements (value=FALSE), or
# of the matched (value=TRUE)
grep("Ba", words, value=FALSE)
# [1] 2 3
grep("Ba", words, value=TRUE)
# [1] "Bar" "Baz"
# { Lowercase and uppercase
grep("o", words, value=TRUE)
# [1] "Foo" "Two"
grep("[Oo]", words, value=TRUE)
# [1] "Foo" "One" "Two"
# Perhaps the simplest case:
grep("o", words, value=TRUE, ignore.case=TRUE)
# [1] "Foo" "One" "Two"
# }
colors()[grep('red', colors())]
# [1] "darkred" "indianred" "indianred1" "indianred2"
# [5] "indianred3" "indianred4" "mediumvioletred" "orangered"
# [9] "orangered1" "orangered2" "orangered3" "orangered4"
# [13] "palevioletred" "palevioletred1" "palevioletred2" "palevioletred3"
# [17] "palevioletred4" "red" "red1" "red2"
# [21] "red3" "red4" "violetred" "violetred1"
# [25] "violetred2" "violetred3" "violetred4"