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。有人请说明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'本身就是8，显然。
'\t\t'是16。
'abc\tabc'从3个字符开始，然后一个标签将其推送到8，然后最后一个'abc'将其从8推送到11 ...
'abc\tabc\tabc'同样从3开始，标签将其变为8，另一个'abc'变为11，然后另一个标签将其推至16，最后'abc'将长度设为19

Answer 2

该选项卡将列指针递增到8的下一个倍数：

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

Python扩展选项卡长度计算

2 个答案: