Python扩展选项卡长度计算

Question

我很困惑使用expandtabs时如何计算字符串的长度.我认为expandtabs用适当数量的空格替换制表符(每个制表符的默认空格数为8).但是,当我使用不同长度和不同数量的选项卡的字符串运行命令时,长度计算与我认为的不同(即,每个选项卡并不总是导致每个实例的字符串长度增加8 "/ t").

下面是一个详细的脚本输出,其中的注释解释了我认为应该是上面执行的命令的结果.有人请解释在使用扩展标签时如何计算长度？

IDLE 2.6.5     
>>> s = '\t'
>>> print len(s)
1
>>> #the length of the string without expandtabs was one (1 tab counted as a single space), as expected.
>>> print len(s.expandtabs())
8
>>> #the length of the string with expandtabs was eight (1 tab counted as eight spaces).
>>> s = '\t\t'
>>> print len(s)
2
>>> #the length of the string without expandtabs was 2 (2 tabs, each counted as a single space).
>>> print len(s.expandtabs())
16
>>> #the length of the string with expandtabs was 16 (2 tabs counted as 8 spaces each).
>>> s = 'abc\tabc'
>>> print len(s)
7
>>> #the length of the string without expandtabs was seven (6 characters and 1 tab counted as a single space).
>>> print len(s.expandtabs())
11
>>> #the length of the string with expandtabs was NOT 14 (6 characters and one 8 space tabs).
>>> s = 'abc\tabc\tabc'
>>> print len(s)
11
>>> #the length of the string without expandtabs was 11 (9 characters and 2 tabs counted as a single space).
>>> print len(s.expandtabs())
19
>>> #the length of the string with expandtabs was NOT 25 (9 characters and two 8 space tabs).
>>>

Answer 1

就像在文本编辑器中输入制表符一样,制表符将长度增加到下一个8的倍数.

所以:

• '\t' 显然,它本身就是8.
• '\t\t' 是16岁.
• 'abc\tabc'从3个字符开始,然后一个标签将其推到8,然后最后一个'abc'将它从8推到11 ......
• 'abc\tabc\tabc'同样从3开始,tab跳到8,另一个'abc'跳到11,然后另一个tab将它推到16,最后'abc'将长度调到19.

Answer 2

该选项卡将列指针增加到8的下一个倍数：

>>> 'abc\tabc'.expandtabs().replace(' ', '*')
'abc*****abc'