Question

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...？该方法应检测单词is并返回YES。

但是，如果NSString为His isn't a mississipi isthmus，则应返回NO。

我尝试使用if ([text rangeOfString:@"is" options:NSCaseInsensitiveSearch].location != NSNotFound) { ... }，但它检测的字符不是单词。

Answer 1

使用“正则表达式”搜索“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!"等字词，其中的字词未被空格包围。

在 Swift 2 中，这将是

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))
}

Swift 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])
}

Answer 2

使用NSRegularExpressionSearch \b选项匹配字边界字符。

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) {//...}

Answer 3

怎么样？

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

Answer 4

您可以按照建议使用正则表达式，也可以用语言分析单词：

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");

在NSStrings中检测整个单词

4 个答案: