Scala regex pattern match groups different from that using findAllIn - regex

Question

I find that the groups extracted by Pattern-matching on regex's in Scala are different from those extracted using findAllIn function.
1) Here is an example of extraction using pattern match -
scala> val fullRegex = """(.+?)=(.+?)""".r
fullRegex: scala.util.matching.Regex = (.+?)=(.+?)
scala> val x = """a='b'"""
x: String = a='b'
scala> x match { case fullRegex(l,r) => println( l ); println(r) }
a
'b'
2) And here is an example of extraction using the findAllIn function -
scala> fullRegex.findAllIn(x).toArray
res4: Array[String] = Array(a=')
I was expecting the returned Array using findAllIn to be Array(a, 'b'). Why is it not so?

Answer 1

This is because you have not specified to what extent the second lazy match should go. So after = it consumes just one character and stops as it is in lazy mode.
See here.
https://regex101.com/r/dU7oN5/10
Change it to .+?=.+ to get full array

Answer 2

In particular, the pattern match's use of unapplySeq uses Matcher.matches, while findAllIn uses Matcher.find. matches tries to match entire input.
scala> import java.util.regex._
import java.util.regex._
scala> val p = Pattern compile ".+?"
p: java.util.regex.Pattern = .+?
scala> val m = p matcher "hello"
m: java.util.regex.Matcher = java.util.regex.Matcher[pattern=.+? region=0,5 lastmatch=]
scala> m.matches
res0: Boolean = true
scala> m.group
res1: String = hello
scala> m.reset
res2: java.util.regex.Matcher = java.util.regex.Matcher[pattern=.+? region=0,5 lastmatch=]
scala> m.find
res3: Boolean = true
scala> m.group
res4: String = h
scala>