如何在Java中刪除二維數組中的特定行和列？

Question

我想從我的參考網絡中刪除一個人，我首先創建原始二維數組的副本，然後通過checkVertex ArrayList重新創建尺寸較小的2D網絡數組，checkVertex是我的唯一頂點列表。所以問題是，當重新填充size-1的新數組[] []是錯誤的，我不太清楚如何解決它。

public static void deletePerson(String name) 
{ 
    //checkVertex is a list of the unique vertices 
    int rowNum = 0; 
    int colNum = 0; 
    int origRows = checkVertex.size() + 1; //+1 is for the [0][0] null spot 
    int origCols = checkVertex.size() + 1; 
    String person = name; 
    String[][] copy = matrix.clone(); 

    for(int x=0; x<checkVertex.size() + 1; x++) 
    { 
     if(matrix[x][0] == null) 
     { 
      //do nothing 
     } 
     else if(matrix[x][0].equalsIgnoreCase(person)) 
     { 
      rowNum = x; 
      break; 
     } 
    } 
    for(int z=0; z<checkVertex.size() + 1; z++) 
    { 
     if(matrix[0][z] == null) 
     { 
      //do nothing 
     } 
     else if(matrix[0][z].equalsIgnoreCase(person)) 
     { 
      colNum = z; 
      break; 
     } 
    } 


    //Now remove them from the list of vertexes 
    for(int i=0; i<checkVertex.size(); i++) 
    { 
     if(checkVertex.get(i).equalsIgnoreCase(person)) 
     { 
      checkVertex.remove(i); 
      break; 
     } 
    } 

    setNum(checkVertex.size()); 

    //Build the sides of the matrix 
    //Starting with the first col 
    matrix = new String[checksSize + 1][checksSize + 1]; 

    for(int x = 0 ; x < checksSize ; x++) 
    { 
     String vertice = checkVertex.get(x); 
     if(x == rowNum) 
     { 
      continue; 
     } 
     else 
     { 
      matrix[x+1][0] = vertice; 
     } 
    } 

    //Now get the top row 
    for(int x = 0 ; x < checksSize ; x++) 
    { 
     String vertice = checkVertex.get(x); 
     if(x == colNum) 
     { 
      continue; 
     } 
     else 
     { 
      matrix[0][x+1] = vertice; 
     } 
    } 

    //Now fill in the references 
    for(int i=1; i<checkVertex.size() + 2; i++) 
    { 
     if(i == rowNum) 
     { 
      continue; 
     } 
     else 
     { 
      for(int j=1; j<checkVertex.size() + 2; j++) 
      { 
       if(j == colNum) 
       { 
        //continue; 
        matrix[i][j-1] = copy[i][j]; 
        j++; 
       } 
       else 
       { 
        matrix[i][j] = copy[i][j]; 
       } 
      }//end for j 
     } 
    }//end for i 

}//END deletePerson(String name) 

Answer 1

，除非你破壞你不能改變現有的陣列數據結構的尺寸，並與新的維度重建它（你必須重新初始化和重新填充）。

編輯：

for(int i=1; i<checkVertex.size() + 2; i++) 

爲什麼+2？新矩陣比原來大嗎？不能。

看看這個程序的結尾，看看它是如何完成的..希望它有幫助。

public static void main(String[] args) { 

     int rows=5; 
     int cols=5; 
     double[][] matrix = new double[rows][cols]; 

     int counter =0; 

     for(int i=0; i<rows; i++) 
     for(int j=0; j<cols; j++){ 

      matrix[i][j] = Math.random(); 
      // counter++; 
      // System.out.println("First test ("+counter+") : " + matrix[i][j]); 

     } 

     //keep copy of original matrix 
     double[][] matrixCopy = matrix.clone(); 

     //Assume 
     int rowToRemove = 2; 
     int colToRemove = 3; 


     // re-initialise matrix with dimension i-1 , j-1 
     matrix = new double[rows-1][cols-1]; 
     counter = 0; 

     //row and column counter for the new matrix 
     int tmpX=-1; 
     int tmpY=-1; 


     //re-populate new matrix by searching through the original copy of matrix, while skipping useless row and column 
     // works only for 1 row and 1 column in a 2d array but by changing the conditional statement we can make it work for n number of rows or columns in a 2d array. 
     for(int i=0; i<rows; i++) 
     { 
     tmpX++; 
     if(i==rowToRemove){ 
      tmpX--; 
     } 
     tmpY=-1; 
      for(int j=0; j<cols; j++){ 


       tmpY++; 
       if(j==colToRemove){ 
       tmpY--; 
       } 

       if(i!=colToRemove&&j!=colToRemove){ 
         counter++; 
        matrix[tmpX][tmpY] = matrixCopy[i][j]; 

        System.out.println(counter+" :"+matrix[tmpX][tmpY]); 
       } 


      } 

     }