Scala has a neat built-in function that turns a string into a regular expression (.r). If you use it on a regular expression with slashes in it, you’ll get errors like so:<\/p>\n
\n\"\\w+\".r\n:1: error: invalid escape character\n \"\\w+\".r\n ^\n<\/pre>\nThus for many regexes, it is preferable to use the multi-line string syntax, as this skips the escaping.<\/p>\n
\nscala> \"\"\"\\w+\"\"\".r\nres43: scala.util.matching.Regex = \\w+\n<\/pre>\nFrom this, we can do some neat things, like find the first word in a sentence:<\/p>\n
\nx.findFirstMatchIn(\"abc def\")\nres44: Option[scala.util.matching.Regex.Match] = Some(abc)\n<\/pre>\nWe can also replace all matches in the string, so if we want to swap one word for another, we can:<\/p>\n
\nx.replaceAllIn(\"abc def\", \"gary\")\nres46: String = gary gary\n<\/pre>\nYou can also apply this to every value in a list, if you want to filter to just items that match. For example, here we filter the list to just values with a single word:<\/p>\n
\nList(\"multi word\", \"12345\", \"word\")\n .filter(\n \"^\\\\w+$\".r\n .findFirstIn(_)\n .isDefined)\n<\/pre>\n\nres2: List[String] = List(12345, word)\n<\/pre>\nThe underscore in allows use to simplify the code, since there is only one thing we’re testing on the value (this is equivalent to writing a lambda, that looks like x => …findFirstIn(x) ).<\/p>\n","protected":false},"excerpt":{"rendered":"
Examples of how to filter strings and lists in scala using regular expressions<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[4],"tags":[480],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t