content是根据网址获得的网页源码字符串

- (NSString *)changeToString:(NSString *)content

{

    NSRegularExpression *regularExpretion=[NSRegularExpression regularExpressionWithPattern:@"<[^>]*>|\n"

                                                                                    options:0

                                                                                      error:nil];

    content = [regularExpretion stringByReplacingMatchesInString:content options:NSMatchingReportProgress range:NSMakeRange(0, content.length) withTemplate:@"-"];         //  替换所有html和换行匹配元素为"-"

    regularExpretion = [NSRegularExpression regularExpressionWithPattern:@"-{1,}" options:0 error:nil] ;

    content = [regularExpretion stringByReplacingMatchesInString:content options:NSMatchingReportProgress range:NSMakeRange(0, content.length) withTemplate:@"-"];          //  把多个"-"匹配为一个"-"

    //  根据"-"分割到数组

    NSArray *arr=[NSArray array];

    content = [NSString stringWithString:content];

    arr =  [content componentsSeparatedByString:@"-"];

    NSMutableArray *marr=[NSMutableArray arrayWithArray:arr];

    [marr removeObject:@""];

    NSMutableString *string = [[NSMutableString alloc] init];

    for (int i = 0; i < arr.count; i++) {

        [string appendString:[NSString stringWithFormat:@"%@",arr[i]]];

    }

    return  string;

}