iOS NSLinguisticTagger 在获取引理词干时总是返回 null

Posted 2023-04-17

【中文标题】iOS NSLinguisticTagger 在获取引理词干时总是返回 null

【英文标题】：iOS NSLinguisticTagger always return null when getting the lemma stem

【发布时间】：2014-05-16 16:13:39

【问题描述】：

我需要将一个关键字（它的词法形式）与一个文本进行匹配，并返回关键字是否匹配（就像搜索引擎一样）

例如

text: I want some apples
keyword: apple
result: matched
keyword: banana
result: not matched

这是我的方法，标签总是为空

- (BOOL)matchKeywordWithText:(NSString *)text keyword:(NSString *)keyword 

    __block NSMutableArray *words = [NSMutableArray array];


    NSLinguisticTaggerOptions options = NSLinguisticTaggerOmitWhitespace | NSLinguisticTaggerOmitPunctuation | NSLinguisticTaggerJoinNames;
    NSLinguisticTagger *tagger = [[NSLinguisticTagger alloc] initWithTagSchemes: [NSLinguisticTagger availableTagSchemesForLanguage:@"en"] options:options];
    tagger.string = text;
    [tagger enumerateTagsInRange:NSMakeRange(0, [text length]) scheme:NSLinguisticTagSchemeLemma options:options usingBlock:^(NSString *tag, NSRange tokenRange, NSRange sentenceRange, BOOL *stop) 
        NSString *token = [text substringWithRange:tokenRange];

        //TODO: TAG IS ALWAYS NULL HERE
        NSLog(@"words are %@: %@", token, tag);

        if (tag.length > 0) 
            [words addObject:tag];
        
    ];

    for (NSString *word in words) 
        if ([word isEqualToString:keyword]) 
            return YES;
        
    

    return NO;

【参考方案1】：

以下代码有效：

NSLinguisticTagger *tagger = [[NSLinguisticTagger alloc]
                              initWithTagSchemes:[NSArray arrayWithObjects:NSLinguisticTagSchemeNameTypeOrLexicalClass, NSLinguisticTagSchemeLemma, nil]
                              options:(NSLinguisticTaggerOmitWhitespace | NSLinguisticTaggerOmitPunctuation)];
NSString *text = @"i'm apples";
[tagger setString:text];
[tagger enumerateTagsInRange:NSMakeRange(0, [text length])
                      scheme:NSLinguisticTagSchemeNameTypeOrLexicalClass
                     options:(NSLinguisticTaggerOmitWhitespace | NSLinguisticTaggerOmitPunctuation)
                  usingBlock:^(NSString *tag, NSRange tokenRange, NSRange sentenceRange, BOOL *stop) 
                      NSString *token = [text substringWithRange:tokenRange];

                      NSString *lemma = [tagger tagAtIndex:tokenRange.location scheme:NSLinguisticTagSchemeLemma tokenRange:NULL sentenceRange:NULL];
                      if (lemma == nil) 
                          lemma = token;
                      

                      NSLog(@"%@, %@", token, lemma);
                  ];

【讨论】：

你能在这里看看我的问题吗？非常令人沮丧..***.com/questions/48768919/…