Question

我正在做＆＃34; Rock，Paper，Scissors＆＃34;游戏，我想检查输入是否与任何数组匹配，现在我有这个代码，它的工作完美：

String[] rockArray = {"Rock","rock","1"},
         paperArray = {"Paper","paper","2"},
         scissorsArray = {"Scissors","scissors","3"};
String[][] answersArray = {rockArray, paperArray, scissorsArray};

//Scanner
Scanner scan = new Scanner(System.in);

// Input
System.out.print("\nRock, Paper or Scissors? -> ");
String answer = scan.next();

 // Checking if the input contains the right values
 while(!Arrays.asList(answerRock).contains(answer) &&
       !Arrays.asList(answerPaper).contains(answer) &&
       !Arrays.asList(answerScissors).contains(answer)) {

         System.out.print("Try again: ");
         answer = scan.next();
 }

但我想说的很简单，这是我的想法，但由于某种原因，它不起作用：

// Here is my arrays 
String[] rockArray = {"Rock","rock","1"},
         paperArray = {"Paper","paper","2"},
         scissorsArray = {"Scissors","scissors","3"};
String[][] globalArray = {rockArray, paperArray, scissorsArray};

// Input
System.out.print("\nRock, Paper or Scissors? -> ");
String answer = scan.next();

//Validation
while(!Arrays.asList(globalArray).contains(answer) {
      System.out.println("Try again: ");
      answer = scan.next();
}

非常感谢！

Answer 1

String[][] globalArray = {rockArray, paperArray, scissorsArray};
...
Arrays.asList(globalArray)

对Arrays.asList()的调用将创建包含3个元素的列表，3个数组，而不是包含数组内容的列表。然后，当您使用contains搜索元素时，您将始终获得false，因为answer将永远不会出现在数组上（如何，String不是List<String> allAnswers = Arrays.asList(rockArray); allAnswers.addAll(Arrays.asList(paperArray)); allAnswers.addAll(Arrays.asList(scissorsArray)); ... while(!allAnswers.contains(answer)) { ...一个数组）。

我建议你这样做：

Arrays.asList()

这也可以避免一遍又一遍地调用<android.support.design.widget.AppBarLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:theme="@style/AppTheme.AppBarOverlay"> <android.support.v7.widget.Toolbar android:id="@+id/toolbar" android:layout_width="match_parent" android:layout_height="?attr/actionBarSize" android:background="?attr/colorPrimary" app:popupTheme="@style/AppTheme.PopupOverlay" /> <android.support.design.widget.TabLayout android:id="@+id/tab_layout" android:layout_width="match_parent" android:layout_height="wrap_content" app:tabGravity="fill" app:tabMode="fixed" /> </android.support.design.widget.AppBarLayout> <android.support.v4.widget.DrawerLayout android:id="@+id/drawer_layout" android:layout_width="match_parent" android:layout_height="match_parent" android:fitsSystemWindows="false" android:textAlignment="center" tools:openDrawer="start"> <android.support.v4.view.ViewPager android:id="@+id/viewpager" android:layout_width="match_parent" android:layout_height="match_parent" app:layout_behavior="@string/appbar_scrolling_view_behavior" /> <android.support.design.widget.NavigationView android:id="@+id/nav_view" android:layout_width="wrap_content" android:layout_height="match_parent" android:layout_gravity="start" android:contextClickable="false" android:fitsSystemWindows="true" app:headerLayout="@layout/nav_header_main" app:menu="@menu/activity_main_drawer" /> </android.support.v4.widget.DrawerLayout>，从而提高性能。

Answer 2

Arrays.asList(...)不起作用，因为List<String[]>方法会输出List<String>而不是asList(...)。

如果您真的想使用String[] allPossibleInputString，则必须输入SELECT votes.movieID, likes.like_count, dislikes.dislike_count FROM votes LEFT join ( SELECT movieID, count(Vote) as like_count FROM votes WHERE Vote = 'li' GROUP BY movieID ) likes ON likes.movieID = votes.movieID LEFT join ( SELECT movieID, count(Vote) as dislike_count FROM votes WHERE Vote = 'dli' GROUP BY movieID ) likes ON likes.movieID = votes.movieID

Answer 3

您的第二个代码段不起作用，因为您无法执行此类!Arrays.asList(globalArray).contains(answer)之类的操作。

一种解决方案是将三个数组的内容复制到全局数组中，如下所示：

String[] rockArray = {"Rock","rock","1"},
         paperArray = {"Paper","paper","2"},
         scissorsArray = {"Scissors","scissors","3"};
String[] globalArray = new String[9];
/* Copy Contents To Global Array */
System.arraycopy(rockArray, 0, globalArray, 0, 3);
System.arraycopy(paperArray, 0, globalArray, 3, 3);
System.arraycopy(scissorsArray, 0, globalArray, 6, 3);

现在你可以这样做：

while(!Arrays.asList(globalArray).contains(answer)) {
    System.out.println("Try again: ");
    answer = scan.nextLine();
}

通过while循环进行数组验证

3 个答案: