Scala regular expression with $ (end of string)

Question

I'm somewhat in difficulty. (I'm pro in regexps but not much used them in scala/java). I have numeric string of 11 chars in length, need just last 10, so:

val Pattern = """(\d{10})$""".r
"79283767219" match {
  case Pattern(m) => m
}

It gives MatchError, but why?! What have I misunderstood?

Answer 1

When you match against a regex pattern, the regex pattern should match the whole string. That is, it's like the regex pattern started with ^ and ended with $. The reason behind this is that a match is supposed to deconstruct the whole of the left side on the right side.

With Scala 2.10, you can call unanchored to get a matcher that will do partial matches, like this:

val Pattern = """(\d{10})$""".r.unanchored

Be assured that your anchor will be preserved. It's just the expectation that the match should apply over the whole string that will be dropped.