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/gaborcsardi/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"github_repos <- c("metacran/crandb", "jeroenooms/curl@v0.9.3",
"jimhester/covr#47", "hadley/dplyr@*release",
"r-lib/remotes@550a3c7d3f9e1493a2ba",
"/$&@R64&3")
owner_rx <- "(?:(?<owner>[^/]+)/)?"
repo_rx <- "(?<repo>[^/@#]+)"
subdir_rx <- "(?:/(?<subdir>[^@#]*[^@#/]))?"
ref_rx <- "(?:@(?<ref>[^*].*))"
pull_rx <- "(?:#(?<pull>[0-9]+))"
release_rx <- "(?:@(?<release>[*]release))"
ref_or_pull_or_release_rx <-
sprintf("(?:%s|%s|%s)?", ref_rx, pull_rx, release_rx)
github_rx <- sprintf("^(?:%s%s%s%s|(?<catchall>.*))$",
owner_rx, repo_rx, subdir_rx, ref_or_pull_or_release_rx)
out <- re_match(text = github_repos, pattern = github_rx)
out#> .match owner repo subdir
#> [1,] "metacran/crandb" "metacran" "crandb" ""
#> [2,] "jeroenooms/curl@v0.9.3" "jeroenooms" "curl" ""
#> [3,] "jimhester/covr#47" "jimhester" "covr" ""
#> [4,] "hadley/dplyr@*release" "hadley" "dplyr" ""
#> [5,] "r-lib/remotes@550a3c7d3f9e1493a2ba" "r-lib" "remotes" ""
#> [6,] "/$&@R64&3" "" "" ""
#> ref pull release catchall
#> [1,] "" "" "" ""
#> [2,] "v0.9.3" "" "" ""
#> [3,] "" "47" "" ""
#> [4,] "" "" "*release" ""
#> [5,] "550a3c7d3f9e1493a2ba" "" "" ""
#> [6,] "" "" "" "/$&@R64&3"MIT © Mango Solutions; Posit Software, PBC