如何删除具有相同属性值但在NSMutableArray中具有相同属性值的所有对象

Question

我有一个带有url字符串属性和标题的历史对象.我想使用包含搜索字符串的url搜索所有对象的历史记录,然后删除所有重复项.

示例:我有一系列历史记录对象,其中20个都是" https://www.google.com ",其中4个是" https://www.google.com/#q=search ",我想获得一个数组后面只有一个对象,其网址值为" https://www.google.com ",网址值为" https://www.google.com/#q=search "

这是我当前的代码,它搜索历史记录并返回与字符串匹配的所有对象:

    - (NSArray *)historyObjectsContainingQuery:(NSString *)query {
    NSMutableArray *matchingObjects = [[NSMutableArray alloc] init];
    HistoryManager *HM = [HistoryManager sharedInstance];
    for (int i=0; i<[[HM history] count]; i++) {
        //History "days"
        HistoryObject *historyItem = HistoryObject([[HistoryManager sharedInstance] history][i]);

        for (int o=0; o<[historyItem.objects count]; o++) {
            //Each object inn each history day
            HistoryObject *HO = HistoryObject(historyItem.objects[o]);
            if ([HO.title rangeOfString:query options:NSCaseInsensitiveSearch].location != NSNotFound) {
                //history objects with their title containing the query string
                [matchingObjects addObject:HO];
            }
        }
    }
    return matchingObjects;
}

然后我记录每个网址值:

self.foundInBookmarksAndHistory = [self historyObjectsContainingQuery:textField.text]; for(HistoryObject*HO in self.foundInBookmarksAndHistory){NSLog(@"%@",HO.url); }

这是结果:

https://www.google.com/
2013-09-15 13:48:49.382 Flow HD[3599:60b] https://www.google.com/
2013-09-15 13:48:49.384 Flow HD[3599:60b] https://www.google.com/
2013-09-15 13:48:49.385 Flow HD[3599:60b] https://www.google.com/
2013-09-15 13:48:49.387 Flow HD[3599:60b] https://www.google.com/
2013-09-15 13:48:49.388 Flow HD[3599:60b] https://www.google.com/
2013-09-15 13:48:49.390 Flow HD[3599:60b] https://www.google.com/
2013-09-15 13:48:49.391 Flow HD[3599:60b] https://www.google.com/search?q=yahoo
2013-09-15 13:48:49.392 Flow HD[3599:60b] https://www.google.com/
2013-09-15 13:48:49.394 Flow HD[3599:60b] https://www.google.com/
2013-09-15 13:48:49.395 Flow HD[3599:60b] https://www.google.com/search?q=Sup
2013-09-15 13:48:49.397 Flow HD[3599:60b] https://www.google.com/
2013-09-15 13:48:49.398 Flow HD[3599:60b] https://www.google.com/
2013-09-15 13:48:49.400 Flow HD[3599:60b] https://www.google.com/
2013-09-15 13:48:49.402 Flow HD[3599:60b] https://www.google.com/
2013-09-15 13:48:49.404 Flow HD[3599:60b] https://www.google.com/
2013-09-15 13:48:49.405 Flow HD[3599:60b] https://www.google.com/

还有很多,我如何删除具有相同值的每个对象？对象不相等,但确实有相同的URL.

我已经尝试过NSPredicate并使用更多的for循环来查找匹配的对象,但我总是留下2个或更多具有相同属性的相同对象.

Answer 1

你可以这样做:

NSMutableSet *seenObjects = [NSMutableSet set];
NSPredicate *dupPred = [NSPredicate predicateWithBlock: ^BOOL(id obj, NSDictionary *bind) {
    HistoryObject *hObj = (HistoryObject*)obj;
    BOOL seen = [seenObjects containsObject:hObj.title];
    if (!seen) {
        [seenObjects addObject:hObj.title];
    }
    return !seen;
}];
NSArray *yourHistoryArray = ... // This is your array which needs to be filtered
NSArray *yourHistoryArray = [yourHistoryArray filteredArrayUsingPredicate:dupObjectsPred];