Scala：重新分配给val
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Scala : reassignment to val
提问by user1993412
I am looking for a way to resolve the below compilation error in Scala. Where , I am trying to update the value of a variable clinSig , if the clinSig is null while calling method1.
我正在寻找一种方法来解决 Scala 中的以下编译错误。哪里，我试图更新变量 clinSig 的值，如果调用 method1 时 clinSig 为空。
import org.joda.time.Instant
import java.util.Calendar
class TestingClass {
method1(null)
private def method1 (clinSig : Instant) {
if (clinSig == null) {
val calendar = Calendar.getInstance()
calendar.set(2011, 0, 5, 0, 0, 0)
calendar.set(Calendar.MILLISECOND, 0)
clinSig = new Instant(calendar.getTime)
}
print(clinSig)
}
}
error: reassignment to val
[INFO] clinSigUpdtDtTm = new Instant(calendar.getTime)
Any inputs would be helpful.
任何输入都会有所帮助。
Thanks !!!
谢谢 ！！！
回答by Lee
Method parameters are vals so you can't re-assign them. You can create a new valand assign that based on the condition:
方法参数是vals，因此您不能重新分配它们。您可以创建一个新的val并根据条件分配它：
val updated = if (clinSig == null) {
val calendar = Calendar.getInstance()
calendar.set(2011, 0, 5, 0, 0, 0)
calendar.set(Calendar.MILLISECOND, 0)
new Instant(calendar.getTime)
}
else clinSig
println(updated)
