仅从字符串中分离后缀

Question

我有一个单词后缀列表，我的目的是将输入的句子分成列表中的后缀。

我的问题是这个列表中的后缀甚至在词根处也将单词分开。例如：

（国际）>>应该是>>（interna _tion _al _ly），我的代码输出是>>（int _erna _tion _al _ly）

注意：我的列表中有“er”

一种解决方案是从句子末尾开始搜索单词。例如，如果匹配列表，代码首先添加字母“y”，然后将其分隔，如果不匹配，则继续添加>“ly”分隔，因为它匹配，然后重置并继续“l”>“al”并将其分开并继续。再这样下去，“erna”就不会匹配和分裂了。

如果它以这种方式搜索，问题就会消失，但我找不到解决方法。

如果你给我指路，我会很高兴的。

sentence = input()
suffixes = ["acy", "ance", "ence", "dom", "er", "or", "ism", "ist",
         "ty", "ment", "ness", "ship", "sion", "tion", "ate",
        "en", "fy", "ize", "able", "ible", "al",
        "esque", "ful", "ic", "ous", "ish", "ive",
        "less", "ed", "ing", "ly", "ward", "wise"]

for x in suffixes:
    y = " _" + x
    sentence = sentence.replace(x, y)

Answer 1

这是一种使用endswith() 和字符串切片的方法：

suffixes = ["acy", "ance", "ence", "dom", "er", "or", "ism", "ist",
            "ty", "ment", "ness", "ship", "sion", "tion", "ate",
            "en", "fy", "ize", "able", "ible", "al",
            "esque", "ful", "ic", "ous", "ish", "ive",
            "less", "ed", "ing", "ly", "ward", "wise"]

def find_suffix(word):
    for suffix in suffixes:
        if word.endswith(suffix):
            suffix_removed = word[:-len(suffix)] # part before suffix
            return find_suffix(suffix_removed) + f' _{suffix}' # recurse
    return word # if no suffix is found, return the word as is

print(find_suffix('internationally')) # interna _tion _al _ly
print(find_suffix('egoistically')) # ego _ist _ic _al _ly

递归不是必需的；只需使用 for 循环即可。

在 Python 3.9 中，they introduced a methodremovesuffix() 为字符串，其定义与上面的代码基本相同。如果您使用的是 Python 3.9+，则可以改为使用 suffix_removed = word.removesuffix(suffix) 以提高可读性（尽管我使用 3.8 后没有对此进行测试）。

---

根据 OP 的要求，以下是将上述内容应用于句子中每个单词的函数。

def suffixify_sentence(sentence):
    return ' '.join(find_suffix(word) for word in sentence.split())

sentence = 'humanity internationally faithfully picturesque'
print(suffixify_sentence(sentence)) # humani _ty interna _tion _al _ly faith _ful _ly pictur _esque

Answer 2

str.replace() 是问题所在。它替换子字符串anywhere，而不仅仅是在末尾。相反，您可以使用 str.endswith()，或者如果您使用的是 3.9+，则可以使用 str.removesuffix()。

这是一个使用str.endswith() 的迭代实现。

def remove_suffixes(string, suffixes):
    """
    Remove all suffixes from string. Return the root and suffixes.

    >>> remove_suffixes('smartly', ['y', 'ly'])
    ('smart', ['ly'])
    """
    # Sort to ensure the longest ones match first
    suffixes = sorted(suffixes, key=len, reverse=True)
    removed = []
    prev = None  # Loop variable
    while prev != string:  # i.e. break if unchanged
        prev = string  # Copy for next loop
        for suffix in suffixes:
            if string.endswith(suffix):
                removed.append(suffix)
                string = string[:-len(suffix)]
    return string, removed[::-1]

suffixes = [
    "acy", "ance", "ence", "dom", "er", "or", "ism", "ist",
    "ty", "ment", "ness", "ship", "sion", "tion", "ate",
    "en", "fy", "ize", "able", "ible", "al",
    "esque", "ful", "ic", "ous", "ish", "ive",
    "less", "ed", "ing", "ly", "ward", "wise"]

s_out, found = remove_suffixes('internationally', suffixes)
# > 'interna', ['tion', 'al', 'ly']
print(s_out, *found, sep=' _')  # -> interna _tion _al _ly

Answer 3

我不确定您的算法是否适用于所有情况，但实现起来似乎很有趣，所以在这里

sentence = 'internationally'
sentence = list(sentence)
stack = []
results = []
for i in sentence[::-1]:
    stack.insert(0,i)
    guess = ''.join(stack)
    if guess in suffixes:
        results.insert(0, f'_{guess}')
        stack = []

results.insert(0, guess)
    
print(''.join(results))
# interna_tion_al_ly    

你实际上实现了一个堆栈并向后构建它

Answer 4

你可以的

max_length = max(len(suffix) for suffix in suffixes)
for suffix_length in range(max_length):
    if suffix_length >= len(word):
        break
    if word[-suffix_length:] in suffixes:
        #split suffix

另一种策略是以增加长度的方式遍历后缀。您可以通过在遍历后缀之前使用 suffixes = sorted(suffixes, key = len) 来做到这一点。即：

sentence = input()
suffixes = ["acy", "ance", "ence", "dom", "er", "or", "ism", "ist",
     "ty", "ment", "ness", "ship", "sion", "tion", "ate",
    "en", "fy", "ize", "able", "ible", "al",
    "esque", "ful", "ic", "ous", "ish", "ive",
    "less", "ed", "ing", "ly", "ward", "wise"]

suffixes = sorted(suffixes, key = len)
for x in suffixes:
    y = " _" + x
    sentence = sentence.replace(x, y)