Match Regular Expressions with a Nicer 'API'
A small wrapper on 'regexpr' to extract the matches and captured groups from the match of a regular expression to a character vector.
source("https://install-github.me/MangoTheCat/rematch")library(rematch)dates <- c("2016-04-20", "1977-08-08", "not a date", "2016",
"76-03-02", "2012-06-30", "2015-01-21 19:58")
isodate <- "([0-9]{4})-([0-1][0-9])-([0-3][0-9])"
re_match(text = dates, pattern = isodate)#> .match
#> [1,] "2016-04-20" "2016" "04" "20"
#> [2,] "1977-08-08" "1977" "08" "08"
#> [3,] NA NA NA NA
#> [4,] NA NA NA NA
#> [5,] NA NA NA NA
#> [6,] "2012-06-30" "2012" "06" "30"
#> [7,] "2015-01-21" "2015" "01" "21"isodaten <- "(?<year>[0-9]{4})-(?<month>[0-1][0-9])-(?<day>[0-3][0-9])"
re_match(text = dates, pattern = isodaten)#> .match year month day
#> [1,] "2016-04-20" "2016" "04" "20"
#> [2,] "1977-08-08" "1977" "08" "08"
#> [3,] NA NA NA NA
#> [4,] NA NA NA NA
#> [5,] NA NA NA NA
#> [6,] "2012-06-30" "2012" "06" "30"
#> [7,] "2015-01-21" "2015" "01" "21"MIT © Mango Solutions