Getting a substring from a list of strings - regex

Question

So, as part of learning the language, I wanted to check three strings for a certain pattern and return the first match of that pattern only.
My attempt was to use a combination of find and regular expressions to traverse the list:
def date = [
"some string",
"some other string 11.11.2000",
"another one 20.10.1990"
].find { title ->
title =~ /\d{2}\.\d{2}\.\d{4}/
}
This kind of works, leaving the whole string in date.
My goal, however, would be to end up with "11.11.2000" in date; I assume somehow I should be able to access the capture group, but how?

Answer 1

If you want to return a specific value when finding a matching element in a collection (which as in your case might be part of that element), you need to use findResult.
Your code might then look like this
def date = [
"some string",
"some other string 11.11.2000",
"another one 20.10.1990"
].findResult { title ->
def res = title =~ /\d{2}\.\d{2}\.\d{4}/
if (res) {
return res[0]
}
}

Answer 2

Extending UnholySheep's answer, you can also do this:
assert [
"some string",
"some other string 11.11.2000",
"another one 20.10.1990"
].findResult { title ->
def matcher = title =~ /\d{2}\.\d{2}\.\d{4}/
matcher.find() ? matcher.group() : null
} == '11.11.2000'
For all matches, just use findResults instead of findResult, like this:
assert [
"some string",
"some other string 11.11.2000",
"another one 20.10.1990"
].findResults { title ->
def matcher = title =~ /\d{2}\.\d{2}\.\d{4}/
matcher.find() ? matcher.group() : null
} == ['11.11.2000', '20.10.1990']