Python编程缩进问题

Question

我想知道是否有人可以阅读这段代码并告诉我为什么会这样。我不是第一个遇到这个问题的人，但我环顾四周，无法在书中或其他地方找到答案。

这一定是小事，但我看不到。

# This program will find and calculte the radius
# area and circumference of a circle.

def main():
    print('Radius\tArea\tCircumference')
    print('----------------------------')
    print()
    for radius in range(1, 11):
        for area in range(1, 11):
            for circumference in range(1, 11):
                pi = 3.14
                diameter = radius * 2
                radius = diameter / 2
                area = pi * radius**2
                circumference = (2 * pi) * radius

        print(radius, '\t', area, '\t',format(circumference, '.2f'))



main()

输出:

Radius  Area    Circumference
----------------------------

1.0      3.14    6.28
2.0      12.56   12.56
3.0      28.26   18.84
4.0      50.24   25.12
5.0      78.5    31.40
6.0      113.04      37.68
7.0      153.86      43.96
8.0      200.96      50.24
9.0      254.34      56.52
10.0     314.0   62.80
>>> 

输出在前两列中对齐，但第三列中十个中的四个似乎在右侧制表符。 ??

Answer 1

为了保证对齐，可以先把每个数字做成固定宽度的字符串。

def main():
    print('Radius\tArea\tCircumference')
    print('----------------------------')
    print()
    for radius in range(1, 11):
        for area in range(1, 11):
            for circumference in range(1, 11):
                pi = 3.14
                diameter = radius * 2
                radius = diameter / 2
                area = pi * radius**2
                circumference = (2 * pi) * radius

        #print(radius, '\t', area, '\t' , format(circumference, ".2f"))
        radius_str        = "%0.2f" % radius
        area_str          = "%0.2f" % area
        circumference_str = "%0.2f" % circumference
        print("%6s\t%6s\t%6s" % (radius_str, area_str, circumference_str))

main()

输出:

Radius  Area    Circumference
----------------------------

  1.00    3.14    6.28
  2.00   12.56   12.56
  3.00   28.26   18.84
  4.00   50.24   25.12
  5.00   78.50   31.40
  6.00  113.04   37.68
  7.00  153.86   43.96
  8.00  200.96   50.24
  9.00  254.34   56.52
 10.00  314.00   62.80