如何打印二維數組的一部分

Question

例如，我想打印四分之一或二維數組的某個部分，我將如何更改下面的代碼。只是一般只打印一樣，如果有十行和列的某些部分我會如何打印最後2行和最後2列，

for (int row = 0; row < example.length; row++) { 
for (int column = 0; column < example[row].length; column++) {  
    System.out.print(" "+example[row][column] + "\t|"); 
    } 
    System.out.println(); 
    } 

Answer 1

你應該改變循環次數根據您想打印。舉例來說，

for (int row = 0; row < (example.length)/2; row++) 
{ 
    for (int column = 0; column < (example.length)/2; column++) 
    {  
     System.out.print(" "+example[row][column] + "\t|"); 
    } 
    System.out.println(); 
} 

這將打印一半的行和列。

Answer 2

您可以嘗試使用循環再生：

String[][] example = new String[][] { { "a", "b", "c", "d" }, { "e", "f", "g", "h" } }; 

for (int row = 0; row < example.length; row++) { 
    for (int column = 0; column < example[row].length/2; column++) { 
     System.out.print(" " + example[row][column] + "\t|"); 
    } 
    System.out.println(); 
} 
System.out.println("----------------------------------------"); 
for (int row = 0; row < example.length/2; row++) { 
    for (int column = 0; column < example[row].length; column++) { 
     System.out.print(" " + example[row][column] + "\t|"); 
    } 
    System.out.println(); 
} 
System.out.println("----------------------------------------"); 
for (int row = example.length/2; row < example.length; row++) { 
    for (int column = 0; column < example[row].length; column++) { 
     System.out.print(" " + example[row][column] + "\t|"); 
    } 
    System.out.println(); 
} 
System.out.println("----------------------------------------"); 
for (int row = 0; row < example.length; row++) { 
    for (int column = example[row].length/2; column < example[row].length; column++) { 
     System.out.print(" " + example[row][column] + "\t|"); 
    } 
    System.out.println(); 
} 
System.out.println("----------------------------------------"); 
for (int row = 0; row < example.length; row++) { 
    for (int column = example[row].length/4; column < example[row].length; column++) { 
     System.out.print(" " + example[row][column] + "\t|"); 
    } 
    System.out.println(); 
} 
System.out.println("----------------------------------------"); 
for (int row = 0; row < example.length; row++) { 
    for (int column = example[row].length * 3/4; column < example[row].length; column++) { 
     System.out.print(" " + example[row][column] + "\t|"); 
    } 
    System.out.println(); 
} 
System.out.println("----------------------------------------"); 

輸出：

a | b | 
e | f | 
---------------------------------------- 
a | b | c | d | 
---------------------------------------- 
e | f | g | h | 
---------------------------------------- 
c | d | 
g | h | 
---------------------------------------- 
b | c | d | 
f | g | h | 
---------------------------------------- 
d | 
h | 
---------------------------------------- 

Answer 3

您可以使用掃描儀將採取定製ROW和COL值。當然，您需要檢查提供的值是否在打印之前的長度中，以免發生任何IndexOutOfBounds錯誤（未在此處顯示）。

int[][] example = new int[10][10]; 

    int count = 0; 

//populate array 

    for (int row = 0; row < example.length; row++) { 
     for (int column = 0; column < example[row].length; column++) {  
      example[row][column] = count; 
      count++; 
     } 
    } 

    Scanner sc = new Scanner(System.in); 
    System.out.println("Enter row start: "); 
    int rowStart = sc.nextInt(); 

    System.out.println("Enter row end: "); 
    int rowEnd = sc.nextInt(); 

    System.out.println("Enter col start: "); 
    int colStart = sc.nextInt(); 

    System.out.println("Enter col end: "); 
    int colEnd = sc.nextInt(); 

    for (int row = rowStart; row < rowEnd; row++) { 
     for (int column = colStart; column < colEnd; column++) {  
      System.out.print(" "+example[row][column] + "\t|"); 
     } 
     System.out.println(); 
    } 
    sc.close();