在Python中，我们可以使用嵌套循环来输出九九乘法表。让我们来看一下正序输出的九九乘法表：

for i in range(1, 10):
    for j in range(1, i+1):
        print(f"{j} * {i} = {i*j}", end="\t")
    print()

正序输出的九九乘法表如下所示：

1 * 1 = 1

1 * 2 = 2 2 * 2 = 4

1 * 3 = 3 2 * 3 = 6 3 * 3 = 9

1 * 4 = 4 2 * 4 = 8 3 * 4 = 12 4 * 4 = 16

1 * 5 = 5 2 * 5 = 10 3 * 5 = 15 4 * 5 = 20 5 * 5 = 25

1 * 6 = 6 2 * 6 = 12 3 * 6 = 18 4 * 6 = 24 5 * 6 = 30 6 * 6 = 36

1 * 7 = 7 2 * 7 = 14 3 * 7 = 21 4 * 7 = 28 5 * 7 = 35 6 * 7 = 42 7 * 7 = 49

1 * 8 = 8 2 * 8 = 16 3 * 8 = 24 4 * 8 = 32 5 * 8 = 40 6 * 8 = 48 7 * 8 = 56 8 * 8 = 64

1 * 9 = 9 2 * 9 = 18 3 * 9 = 27 4 * 9 = 36 5 * 9 = 45 6 * 9 = 54 7 * 9 = 63 8 * 9 = 72 9 * 9 = 81

现在，让我们来看一下倒序输出的九九乘法表：

for i in range(9, 0, -1):
    for j in range(1, i+1):
        print(f"{j} * {i} = {i*j}", end="\t")
    print()

倒序输出的九九乘法表如下所示：

1 * 9 = 9 2 * 9 = 18 3 * 9 = 27 4 * 9 = 36 5 * 9 = 45 6 * 9 = 54 7 * 9 = 63 8 * 9 = 72 9 * 9 = 81

1 * 8 = 8 2 * 8 = 16 3 * 8 = 24 4 * 8 = 32 5 * 8 = 40 6 * 8 = 48 7 * 8 = 56 8 * 8 = 64

1 * 7 = 7 2 * 7 = 14 3 * 7 = 21 4 * 7 = 28 5 * 7 = 35 6 * 7 = 42 7 * 7 = 49

1 * 6 = 6 2 * 6 = 12 3 * 6 = 18 4 * 6 = 24 5 * 6 = 30 6 * 6 = 36

1 * 5 = 5 2 * 5 = 10 3 * 5 = 15 4 * 5 = 20 5 * 5 = 25

1 * 4 = 4 2 * 4 = 8 3 * 4 = 12 4 * 4 = 16

1 * 3 = 3 2 * 3 = 6 3 * 3 = 9

1 * 2 = 2 2 * 2 = 4

1 * 1 = 1

通过以上代码，我们可以看到，倒序输出的九九乘法表是按照每行数字个数递减的方式排列的。

希望以上内容能帮助到你，如果还有其他问题，请随时提问。

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