java - 按列打印 Java 数组

Question

我正在尝试在 Java 中格式化两个数组以打印如下内容:

Inventory Number      Books                          Prices
------------------------------------------------------------------
1                     Intro to Java                  $45.99
2                     Intro to C++                   $89.34
3                     Design Patterns                $100.00
4                     Perl                           $25.00

我正在使用以下代码:

for(int i = 0; i < 4; i++) {
        System.out.print(i+1);
        System.out.print("                     " + books[i] + " ");
        System.out.print("                 " + "$" + booksPrices[i] + " ");
        System.out.print("\n");
    }

但是我却得到了这个格式错误的结果:

Inventory Number      Books                          Prices
------------------------------------------------------------------
1                     Intro to Java                  $45.99 
2                     Intro to C++                  $89.34 
3                     Design Patterns                  $100.0 
4                     Perl                  $25.0 

如何将所有列直接排列在顶部标题下方？

有更好的方法来做到这一点吗？

Answer 1

您应该查看格式:

System.out.format("%15.2f", booksPrices[i]);   

这将提供 15 个插槽，并在需要时用空格填充。

但是，我注意到您没有右对齐数字，在这种情况下您希望在书籍字段上左对齐:

System.out.printf("%-30s", books[i]);

这是一个工作片段示例:

String books[] = {"This", "That", "The Other Longer One", "Fourth One"};
double booksPrices[] = {45.99, 89.34, 12.23, 1000.3};
System.out.printf("%-20s%-30s%s%n", "Inventory Number", "Books", "Prices");
for (int i=0;i<books.length;i++){
    System.out.format("%-20d%-30s$%.2f%n", i, books[i], booksPrices[i]);
}

结果:

Inventory Number    Books                         Prices
0                   This                          $45.99
1                   That                          $89.34
2                   The Other Longer One          $12.23
3                   Fourth One                    $1000.30