如何在Python中获得合并Unicode字符串的“可见”长度?

If I have a Python Unicode string that contains combining characters, len reports a value that does not correspond to the number of characters "seen".

如果我有一个包含组合字符的Python Unicode字符串，len会报告一个与“已见”字符数量不一致的值。

For example, if I have a string with combining overlines and underlines such as u'A\u0332\u0305BC', len(u'A\u0332\u0305BC') reports 5; but the displayed string is only 3 characters long.

例如，如果我有一个字符串，它结合了overlines和下划线，比如u' a \u0332\u0305BC'， len(u' a \u0332\u0305BC')报告5;但是显示的字符串只有3个字符长。

How do I get the "visible" — that is, number of distinct positions occupied by the string the user sees — length of a Unicode string containing combining glyphs in Python?

如何获得“可见的”——即用户看到的字符串占用的不同位置的数量——包含Python中的组合符号的Unicode字符串的长度?

3 个解决方案

#1

The unicodedata module has a function combining that can be used to determine if a single character is a combining character. If it returns 0 you can count the character as non-combining.

unicodedata模块具有一个组合函数，可用于确定单个字符是否是组合字符。如果返回0，则可以将字符计数为非组合。

import unicodedata
len(u''.join(ch for ch in u'A\u0332\u0305BC' if unicodedata.combining(ch) == 0))

or, slightly simpler:

或者,稍微简单一点:

sum(1 for ch in u'A\u0332\u0305BC' if unicodedata.combining(ch) == 0)

#2

If you have a regex flavor that supports matching grapheme, you can use \X

如果您有支持匹配字符的regex风格，您可以使用\X

Demo

演示

While the default Python re module does not support \X, Matthew Barnett's regex module does:

虽然默认的Python re模块不支持\X，但是Matthew Barnett的regex模块是这样做的:

>>> len(regex.findall(r'\X', u'A\u0332\u0305BC'))
3

On Python 2, you need to use u in the pattern:

在Python 2中，您需要在模式中使用u:

>>> regex.findall(u'\\X', u'A\u0332\u0305BC')
[u'A\u0332\u0305', u'B', u'C']
>>> len(regex.findall(u'\\X', u'A\u0332\u0305BC'))
3

#3

Combining characters are not the only zero-width characters:

组合字符不是唯一的零宽度字符:

>>> sum(1 for ch in u'\u200c' if unicodedata.combining(ch) == 0)
1

("\u200c" or "‌" is zero-width non-joiner; it's a non-printing character.)

(“\ u200c”或“‌”是零宽度non-joiner;这是一个非打印字符。)

In this case the regex module does not work either:

在这种情况下，regex模块也不起作用:

>>> len(regex.findall(r'\X', u'\u200c'))
1

I found wcwidth that handles the above case correctly:

我找到了正确处理上述情况的wcwidth:

>>> from wcwidth import wcswidth
>>> wcswidth(u'A\u0332\u0305BC')
3
>>> wcswidth(u'\u200c')
0

But still doesn't seem to work with user 596219's example:

但用户596219的例子似乎仍然不能说明问题:

>>> wcswidth('각')
4

#1