检测 NSStrings 中的整个单词答案

【问题标题】：Detect whole word in NSStrings检测 NSStrings 中的整个单词
【发布时间】：2013-11-05 09:01:44
【问题描述】：

如何检测 NSString 是否包含特定单词，例如is。

如果 NSString 是Here is my string. His isn't a mississippi isthmus. It is...？该方法应该检测到单词is 并返回YES。

但是，如果 NSString 是His isn't a mississipi isthmus，它应该返回NO。

我尝试使用if ([text rangeOfString:@"is" options:NSCaseInsensitiveSearch].location != NSNotFound) { ... }，但它检测到的是字符而不是单词。

【问题讨论】：

用空格包围搜索到的单词不会检测到最后一个是...

标签： ios objective-c nsstring

【解决方案1】：

使用“正则表达式”搜索与“单词边界模式”\b：

NSString *text = @"Here is my string. His isn't a mississippi isthmus. It is...";
NSString *pattern = @"\\bis\\b";
NSRange range = [text rangeOfString:pattern options:NSRegularExpressionSearch|NSCaseInsensitiveSearch];
if (range.location != NSNotFound) { ... }

这也适用于"Is it?" 或"It is!" 等单词没有被空格包围的情况。

在 Swift 2 中

let text = "Here is my string. His isn't a mississippi isthmus. It is..."
let pattern = "\\bis\\b"
if let range = text.rangeOfString(pattern, options: [.RegularExpressionSearch, .CaseInsensitiveSearch]) {
    print ("found:", text.substringWithRange(range))
}

斯威夫特 3：

let text = "Here is my string. His isn't a mississippi isthmus. It is..."
let pattern = "\\bis\\b"
if let range = text.range(of: pattern, options: [.regularExpression, .caseInsensitive]) {
    print ("found:", text.substring(with: range))
}

斯威夫特 4：

let text = "Here is my string. His isn't a mississippi isthmus. It is..."
let pattern = "\\bis\\b"
if let range = text.range(of: pattern, options: [.regularExpression, .caseInsensitive]) {
    print ("found:", text[range])
}

Swift 5（使用新的原始字符串文字）：

let text = "Here is my string. His isn't a mississippi isthmus. It is..."
let pattern = #"\bis\b"#
if let range = text.range(of: pattern, options: [.regularExpression, .caseInsensitive]) {
    print ("found:", text[range])
}

【讨论】：

【解决方案2】：

使用NSRegularExpressionSearch 选项和\b 来匹配单词边界字符。

像这样：

NSString *string = @"Here is my string. His isn't a mississippi isthmus. It is...";
if(NSNotFound != [string rangeOfString:@"\\bis\\b" options:NSRegularExpressionSearch].location) {//...}

【讨论】：

【解决方案3】：

怎么样

if ([text rangeOfString:@" is " options:NSCaseInsensitiveSearch].location != NSNotFound) { ... }

【讨论】：

【解决方案4】：

您可以按照建议使用正则表达式，也可以从语言上分析单词：

NSString *string = @"Here is my string. His isn't a mississippi isthmus. It is...";
__block BOOL containsIs = NO;
[string enumerateLinguisticTagsInRange:NSMakeRange(0, [string length]) scheme:NSLinguisticTagSchemeTokenType options:NSLinguisticTaggerOmitPunctuation | NSLinguisticTaggerOmitWhitespace | NSLinguisticTaggerOmitOther orthography:nil usingBlock:^(NSString *tag, NSRange tokenRange, NSRange sentenceRange, BOOL *stop){
    NSString *substring = [string substringWithRange:tokenRange];
    if (containsIs)
        if ([substring isEqualToString:@"n't"])
            containsIs = NO; // special case because "isn't" are actually two separate words
        else
            *stop = YES;
    else
        containsIs = [substring isEqualToString:@"is"];
}];
NSLog(@"'%@' contains 'is': %@", string, containsIs ? @"YES" : @"NO");

【讨论】：