需求：

將隨機字串（使用者手動輸入的），例如@"#好的話的哈哈 #哈哈哈,和大河 #很多哈哈的&#開導開導可#好的話的哈哈呵呵呵 #可控####123"

檢索出以@"#"開頭，以@"～＠#￥$％&×－＝＋·_+~*÷ ，。、；！‘’【】、《》？：“”「」|（）……—— ,./;'[] \\ <>?:\"{}|!()…— "結尾的標籤；

類抖音將話題標為黃色，話題標籤位置和長度已經標出，富文字功能很簡單，本篇不再多加贅述。

程式碼

    NSString *allStr = @"#好的話的哈哈 #哈哈哈,和大河 #很多哈哈的&#開導開導可#好的話的哈哈呵呵呵 #可控####123
 
";
    NSString *startStr = @"#";
    NSString *endStr = @"～＠#￥$％&×－＝＋·_+~*÷   ，。、；！‘’【】、《》？：“”「」|（）……——   ,./;'[] \\ <>?:\"{}|!()…—    ";
    
    NSMutableArray *subStrArray =  [[NSMutableArray alloc] init];
    int start = 0;
    int end = 0;
    BOOL isStart = NO;
    NSString *subStr = @""
 
;
    for (int i=1; i<allStr.length; i++) {
        NSString *curStr = [allStr substringWithRange:NSMakeRange(i, 1)];
        NSString *preStr = [allStr substringWithRange:NSMakeRange(i-1, 1)];
        if (!isStart) {
            if (![endStr containsString:curStr] && [startStr containsString:preStr]) {
                isStart 
 
= YES;
                start = i-1;
                end = i-1;
                continue;
            }
        }
        
        if ([endStr containsString:curStr] || i==allStr.length-1) {
            end = i;
        }
        if (end > start && isStart) {
            int length = 0;
            if (end == allStr.length-1 && ![endStr containsString:curStr]) {
                length = end-start+1;
            } else {
                length = end-start;
            }
            subStr = [allStr substringWithRange:NSMakeRange(start, length)];
            
            NSMutableDictionary *subStrDic =  [[NSMutableDictionary alloc] init];
            [subStrDic setObject:[NSString stringWithFormat:@"%d",start] forKey:@"start"];
            [subStrDic setObject:[NSString stringWithFormat:@"%d",length] forKey:@"length"];
            [subStrDic setObject:subStr forKey:@"subStr"];
            [subStrArray addObject:subStrDic];
            NSLog(@"%d %d %@",start,end,subStr);
            isStart = NO;
        }
        
    }
    NSLog(@"%@",subStrArray);

結果：

2020-12-04 16:10:39.657950+0800 Test[46210:8236403] 0 7 #好的話的哈哈
2020-12-04 16:10:39.658085+0800 Test[46210:8236403] 8 12 #哈哈哈
2020-12-04 16:10:39.658255+0800 Test[46210:8236403] 17 23 #很多哈哈的
2020-12-04 16:10:39.658381+0800 Test[46210:8236403] 24 30 #開導開導可
2020-12-04 16:10:39.658540+0800 Test[46210:8236403] 30 40 #好的話的哈哈呵呵呵
2020-12-04 16:10:39.658637+0800 Test[46210:8236403] 41 44 #可控
2020-12-04 16:10:39.658742+0800 Test[46210:8236403] 47 50 #123
2020-12-04 16:10:39.658911+0800 Test[46210:8236403] (
        {
        length = 7;
        start = 0;
        subStr = "#\U597d\U7684\U8bdd\U7684\U54c8\U54c8";
    },
        {
        length = 4;
        start = 8;
        subStr = "#\U54c8\U54c8\U54c8";
    },
        {
        length = 6;
        start = 17;
        subStr = "#\U5f88\U591a\U54c8\U54c8\U7684";
    },
        {
        length = 6;
        start = 24;
        subStr = "#\U5f00\U5bfc\U5f00\U5bfc\U53ef";
    },
        {
        length = 10;
        start = 30;
        subStr = "#\U597d\U7684\U8bdd\U7684\U54c8\U54c8\U5475\U5475\U5475";
    },
        {
        length = 3;
        start = 41;
        subStr = "#\U53ef\U63a7";
    },
        {
        length = 4;
        start = 47;
        subStr = "#123";
    }
)