Question

我正在尝试从某些文本中检索图像url字符串，然后创建一个包含所有这些图像url字符串的数组。我想我知道如何使用NSRegularExpression获取图像网址，但我不知道如何获取每个结果。我之前完成了查找和替换，但这只涉及操纵一个巨大的字符串。这是我的代码：

-(NSArray*)parseImages:(NSString*)contents {

    NSArray* imageArray = [[NSArray alloc] init];

    NSError* error = nil;
    NSString* imageHandler = @"\(\?:\\<a\\shref=\"\)https\?:\/\/[\^\/\\s]\+\/\\S\+\\\.\(jpg|png|gif\)";

    NSRegularExpression *imageGrabber = [NSRegularExpression regularExpressionWithPattern:imageHandler options:NSRegularExpressionCaseInsensitive error:&error];
    if (error)
    {
        NSLog(@"Couldn't create regex with given string and options");
        return nil;
    } else {
        //Code to add each individual match to imageArray
    return imageArray;
}

Answer 1

这是我在正则表达式中用于多个匹配的内容：

NSArray *matchesArray = [self rangesOfString:@"{regex}" inString:aString];
for (NSValue *rangeVal in matchesArray)
{
    NSRange range = [rangeVal rangeValue];
    if (range.location != NSNotFound) {
        // do stuff with the found range - like add to an NSMutableArray!
    }
}

并且rangesOfString方法：

- (NSArray *)rangesOfString:(NSString *)searchString inString:(NSString *)str {
    NSMutableArray *results = [NSMutableArray array];
    NSRange searchRange = NSMakeRange(0, [str length]);
    NSRange range;
    while ((range = [str rangeOfString:searchString options:NSRegularExpressionSearch|NSCaseInsensitiveSearch range:searchRange]).location != NSNotFound) {
        [results addObject:[NSValue valueWithRange:range]];
        searchRange = NSMakeRange(NSMaxRange(range), [str length] - NSMaxRange(range));
    }
    return results;
}

Answer 2

让Apple使用NSDataDetector

进行繁重的工作

NSString *text = @"jibberish http://link1.com jibberish http://link2.com jibberish";
NSError *error;
NSDataDetector *dd = [NSDataDetector dataDetectorWithTypes:NSTextCheckingTypeLink error:&error];
NSArray *matches = [dd matchesInString:text options:0 range:NSMakeRange(0, text.length)];

NSMutableArray *links = [NSMutableArray new];
for (NSTextCheckingResult *result in matches) {
    [links addObject:[result URL]];
}
NSLog(@"links: %@", links);

NSLog输出：

链接：（
          ＆＃34; http://link1.com＆＃34 ;,
          ＆＃34; http://link2.com＆＃34;
          ）

如果需要限制扩展类型：

将扩展添加到集合中：

NSSet *extensions = [NSSet setWithArray: @[@"jpg", @"png", @"gif"]];

仅当扩展名在集合中时才添加到数组中：

NSString *ext = [[url resourceSpecifier] pathExtension];
if ([extensions containsObject:ext]) {
    [links addObject:url];
}

返回NSRegularexpression结果数组

2 个答案: