list.contains()
特定の要素があるかを判定し、booleanで返す
public static void main(String[] args) {
String arr[] = {"orange","apple","cherry","melon","grape"};
List<String> list = new ArrayList<>(Arrays.asList(arr));
if(list.contains("banana")) {
System.out.println("存在する");
}else {
System.out.println("存在しない");
}
}
list.indexOf()
特定の要素のINDEX番号をintで返し、存在しない場合は-1を返す
public static void main(String[] args) {
String arr[] = {"orange","apple","cherry","melon","grape"};
List<String> list = new ArrayList<>(Arrays.asList(arr));
int x = list.indexOf("orange");
System.out.println(x);
if(list.indexOf("orange") != -1) {
System.out.println("存在する");
}else {
System.out.println("存在しない");
}
}