如何计算字符串中的字母？

Question

假设我有一个UTF-8 str，例如

my_str = "??????"  # ['?', '?', '?', '?', '?', '?']

我如何找到其中包含多少个字母？len(my_str)返回6，即包含的Unicode代码点数。实际上是4个字母长。

还有一个额外的问题：有些语言将有向图定义为单个字母（例如，“ Dh”是现代阿尔巴尼亚字母的第6个字母），我该如何处理这种边缘情况？

Answer 1

您想对文本进行分段。这是由UAX #29在 Unicode 中管理的。

4个字母长

该术语不正确/太窄，应该说“4 个字形簇长”。

使用uniseg库：

from uniseg.graphemecluster import grapheme_clusters
for text in ('??????', 'Bo\u0304ris', '???????????'):
    print(list(grapheme_clusters(text)))
#['?', '?', '??', '??']
#['B', 'o?', 'r', 'i', 's']
#['???', '??????']

# treat digraph 'dh' as a customised grapheme cluster
def albanian_digraph_dh(s, breakables):
    for i, breakable in enumerate(breakables):
        if s.endswith('d', 0, i) and s.startswith('h', i):
            yield 0
        else:
            yield breakable

# you can do all the digraphs like this
ALBANIAN_DIGRAPHS = {"Dh", "Gj", "Ll", "Nj", "Rr", "Sh", "Th", "Xh", "Zh"}
ALBANIAN_DIGRAPHS |= {digraph.lower() for digraph in ALBANIAN_DIGRAPHS}
def albanian_digraphs(s, breakables):
    for i, breakable in enumerate(breakables):
        yield 0 if s[i-1:i+1] in ALBANIAN_DIGRAPHS else breakable

# from https://sq.wiktionary.org/wiki/Speciale:PrefixIndex?prefix=dh
for text in ('dhallanik', 'dhelpëror', 'dhembshurisht', 'dhevështrues', 'dhimbshëm', 'dhjamosje', 'dhjetëballësh', 'dhjetëminutësh', 'dhogaç', 'dhogiç', 'dhomë-muze', 'dhuratë', 'dhëmbinxhi', 'dhëmbçoj', 'dhëmbëkatarosh'):
    print(list(grapheme_clusters(text, albanian_digraphs)))

#['dh', 'a', 'll', 'a', 'n', 'i', 'k']
#['dh', 'e', 'l', 'p', 'ë', 'r', 'o', 'r']
#['dh', 'e', 'm', 'b', 'sh', 'u', 'r', 'i', 'sh', 't']
#['dh', 'e', 'v', 'ë', 'sh', 't', 'r', 'u', 'e', 's']
#['dh', 'i', 'm', 'b', 'sh', 'ë', 'm']
#['dh', 'j', 'a', 'm', 'o', 's', 'j', 'e']
#['dh', 'j', 'e', 't', 'ë', 'b', 'a', 'll', 'ë', 'sh']
#['dh', 'j', 'e', 't', 'ë', 'm', 'i', 'n', 'u', 't', 'ë', 'sh']
#['dh', 'o', 'g', 'a', 'ç']
#['dh', 'o', 'g', 'i', 'ç']
#['dh', 'o', 'm', 'ë', '-', 'm', 'u', 'z', 'e']
#['dh', 'u', 'r', 'a', 't', 'ë']
#['dh', 'ë', 'm', 'b', 'i', 'n', 'xh', 'i']
#['dh', 'ë', 'm', 'b', 'ç', 'o', 'j']
#['dh', 'ë', 'm', 'b', 'ë', 'k', 'a', 't', 'a', 'r', 'o', 'sh']

你可以安装它

pip install uniseg