Tour of Scala
Regularni izrazi
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Regularni izrazi su stringovi koji se mogu koristiti za traženje uzoraka u podacima.
Bilo koji string se može pretvoriti u regularni izraz pozivom .r metode.
import scala.util.matching.Regex
val numberPattern: Regex = "[0-9]".r
numberPattern.findFirstMatchIn("awesomepassword") match {
case Some(_) => println("Password OK")
case None => println("Password must contain a number")
}
U gornjem primjeru, numberPattern je Regex
(regularni izraz) kojim provjeravamo da li šifra sadrži broj.
Također, možete tražiti grupe regularnih izraza koristeći zagrade.
import scala.util.matching.Regex
val keyValPattern: Regex = "([0-9a-zA-Z-#() ]+): ([0-9a-zA-Z-#() ]+)".r
val input: String =
"""background-color: #A03300;
|background-image: url(img/header100.png);
|background-position: top center;
|background-repeat: repeat-x;
|background-size: 2160px 108px;
|margin: 0;
|height: 108px;
|width: 100%;""".stripMargin
for (patternMatch <- keyValPattern.findAllMatchIn(input))
println(s"key: ${patternMatch.group(1)} value: ${patternMatch.group(2)}")
Ovdje parsiramo ključeve i vrijednosti Stringa. Svaki pogodak ima grupu pod-pogodaka. Ovo je izlaz:
key: background-color value: #A03300
key: background-image value: url(img
key: background-position value: top center
key: background-repeat value: repeat-x
key: background-size value: 2160px 108px
key: margin value: 0
key: height value: 108px
key: width value: 100