在列中打印Java数组

Question

我正在尝试用Java格式化两个数组来打印这样的东西:

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");
    }

但我得到这个格式不佳的结果:

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 

我如何直接在顶部的标题下面排列所有列？

有没有更好的方法来做这个？

Answer 1

你应该看看格式:

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它.

但是,我注意到你没有正确对齐你的数字,在这种情况下你想在书籍领域左对齐:

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]);
}

导致:

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