用int數組的元素初始化字符串

Question

我正在嘗試創建一個toString方法，該方法將返回對象“ Individual”的字符串表示形式。 個體是整數數組。 該字符串應包含對我的排列的介紹，以及數組的索引和元素。

因此理想情況下，字符串應如下所示

  public String toString() {
    System.out.println ("The permutation of this Individual is the following: ");
    for (int i=0; i<size; i++){
      System.out.print (" " + i);
    }
    System.out.println();
    for (int i=0; i<size; i++) {
      System.out.print (" " + individual[i]);
    }
    System.out.println ("Where the top row indicates column of queen, and bottom indicates row of queen");
  }

我一直在堅持如何將特定的表示形式存儲為字符串並設置其格式，尤其是如何將數組元素存儲到字符串中。

Answer 1

您需要一個StringBuilder而不是將其打印出來

 public String toString() {
    StringBuilder builder =new StringBuilder();
    builder.append("The permutation of this Individual is the following: ");
    builder.append("\n");//This to end a line
    for (int i=0; i<size; i++){
       builder.append(" " + i);
    }
    builder.append("\n");
    for (int i=0; i<size; i++) {
       builder.append(" " + individual[i]);
    }
    builder.append("\n");
    builder.append("Where the top row indicates column of queen, and bottom indicates row of queen");
    builder.append("\n");
    return builder.toString();
  }

Answer 2

您可以將數組元素存儲在這樣的字符串中：

String data = ""; // empty
ArrayList items; // array of stuff you want to store into a string

for(int i =0; i< items.size(); i++){
  data+=""+items.get(i) + ","; // appends into a string
} 

// finally return the string, you can put this in a function
return data;