使用宽度说明符打印Python列表

Question

我希望能有更好的方法来实现这个。直接看代码：

print "-I- %-6s%-6s%-6s%-6s%-6s%-6s%-6s%-6s%-8s" % \
      ("A",B","C","D","E","F","G","H","% Done")
print "-I- %-6s%-6s%-6s%-6s%-6s%-6s%-6s%-6s%-8s" % \
      ("-"*5 ,"-"*5 ,"-"*5 ,"-"*5 ,"-"*5 ,"-"*5 ,"-"*5,"-"*5,"-"*8)

理想情况下，我想做这样的事情：

hdrs = ["A",B","C","D","E","F","G","H","% Done"]
<print statement that uses len(hdrs[i]+2) for the column width>
<print statement that uses len(hdrs[i]+2) for the column width and len(hdrs[i]+1 for the number of dashes>

输出结果应该是这样的：

A     B     C
----- ----- -----

这个方法比我现在的方法要灵活得多。我尝试过用 join 和 map 等方法，但一直没能找到一个可行的解决方案。任何帮助都将非常感谢。

编辑：

我刚刚让这一部分工作了：

print " ".join("-"*(len(x)+1) for x in hdrs)

前面的代码行按照我在最初帖子中请求的方式打印了破折号，但我在想是否有更简洁的方法。我仍然搞不清楚如何打印字符串。

Answer 1

你可以这样来构建你的格式字符串：

format = "".join(["%-"+str(len(h)+2)+"s" for h in hdrs])

然后你可以用它来打印你的列表，比如：

l = range(hdrs) # example data to print, the number of items is the same as hdrs
print format % tuple(l)

Answer 2

如果你只是想快速完成这个任务，而不是把它当成练习的话，可以使用prettytable这个工具。下面的例子来自于那个教程：

x = PrettyTable(["City name", "Area", "Population", "Annual Rainfall"])
x.align["City name"] = "l" # Left align city names
x.padding_width = 1 # One space between column edges and contents (default)
x.add_row(["Adelaide",1295, 1158259, 600.5])
x.add_row(["Brisbane",5905, 1857594, 1146.4])
x.add_row(["Darwin", 112, 120900, 1714.7])
x.add_row(["Hobart", 1357, 205556, 619.5])
x.add_row(["Sydney", 2058, 4336374, 1214.8])
x.add_row(["Melbourne", 1566, 3806092, 646.9])
x.add_row(["Perth", 5386, 1554769, 869.4])
print x

输出结果：

+-----------+------+------------+-----------------+
| City name | Area | Population | Annual Rainfall |
+-----------+------+------------+-----------------+
| Adelaide  | 1295 |  1158259   |      600.5      |
| Brisbane  | 5905 |  1857594   |      1146.4     |
| Darwin    | 112  |   120900   |      1714.7     |
| Hobart    | 1357 |   205556   |      619.5      |
| Sydney    | 2058 |  4336374   |      1214.8     |
| Melbourne | 1566 |  3806092   |      646.9      |
| Perth     | 5386 |  1554769   |      869.4      |
+-----------+------+------------+-----------------+

Answer 3

这样怎么样：

hdrs = ("A","B","C","D","E","F","G","H","% Done")
fmt_string = ''.join("%%-%is" % (len(h)+2) for h in hdrs)
print(fmt_string % hdrs)
print(fmt_string % tuple("-"*(len(h)+1) for h in hdrs))

我用了文中提到的列大小，而不是示例中的那些。