我无法从数组输出中删除空值

Question

I want the folowing program to take user input, store it in the array then repeat it back when the user types stop .

However it prints out the rest of the values upto 100 as null , this is what I need to remove. I've tried a few different methods but it's just not working for me.

This is basically what I've got so far (with help from other questions on Stack):

public static void main(String[] args) {

    String[] teams = new String[100];
    String str = null;
    Scanner sc = new Scanner(System.in);
    int count = -1;
    String[] refinedArray = new String[teams.length];

    for (int i = 0; i < 100; i++) {       
       str= sc.nextLine();


       for(String s : teams) {
           if(s != null) { // Skips over null values. Add "|| "".equals(s)" if you want to exclude empty strings
               refinedArray[++count] = s; // Increments count and sets a value in the refined array
           }
       }

       if(str.equals("stop")) {
          Arrays.stream(teams).forEach(System.out::println);
       }

       teams[i] = str;
    }
}

Answer 1

An array as has a fixed size and if you use an array of an any class, you will have null value for indexes of the values not valued.

If you want to have a array with only used values, you could define a variable to store the size really used by array.
And use it to create a new array with the actual size.

Otherwise you could use the original array but iterating only until the actual size of the array when you loop on String[] teams .

String[] teams = new String[100];
int actualSize = 0;
...
for (int i = 0; i < 100; i++) {       
   ...

   teams[i] = str;
   actualSize++;
   ...
}
   ...
String[] actualTeams = new String[actualSize];
System.arraycopy(array, 0, actualTeams, 0, actualSize);

A better way is of course using a structure that adjusts automatically its size such as an ArrayList .

Answer 2

You just need to tell your stream what elements to include. You can change the line constructing the stream:

   if(str.equals("stop")) {
      //stream is called with a beginning and an end indexes.
      Arrays.stream(teams, 0, i).forEach(System.out::println);
   }