Initializing ArrayList with some predefined values
I have an sample program as shown.
I want my ArrayList
symbolsPresent
to be initialized with some predefined symbols: ONE, TWO, THREE, and FOUR.
symbolsPresent.add("ONE");
symbolsPresent.add("TWO");
symbolsPresent.add("THREE");
symbolsPresent.add("FOUR");
import java.util.ArrayList;
public class Test {
private ArrayList<String> symbolsPresent = new ArrayList<String>();
public ArrayList<String> getSymbolsPresent() {
return symbolsPresent;
}
public void setSymbolsPresent(ArrayList<String> symbolsPresent) {
this.symbolsPresent = symbolsPresent;
}
public static void main(String args[]) {
Test t = new Test();
System.out.println("Symbols Present is" + t.symbolsPresent);
}
}
Is that possible?
try this
new String[] {"One","Two","Three","Four"};
or
List<String> places = Arrays.asList("One", "Two", "Three");
ARRAYS
Double brace initialization is an option:
List<String> symbolsPresent = new ArrayList<String>() {{
add("ONE");
add("TWO");
add("THREE");
add("FOUR");
}};
Note that the String
generic type argument is necessary in the assigned expression as indicated by JLS §15.9
It is a compile-time error if a class instance creation expression declares an anonymous class using the "<>" form for the class's type arguments.
如何使用重载的ArrayList构造函数 。
private ArrayList<String> symbolsPresent = new ArrayList<String>(Arrays.asList(new String[] {"One","Two","Three","Four"}));
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