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 搜索对象的所有历史记录，然后删除所有重复项。

例子: 我有一组历史对象，其中 20 个都是“https://www.google.com”，4 个是“https://www.google.com/#q=search”，我想返回一个数组，其中只有一个对象的 url 值为“https://www.google.com”和一个“https://www.google.com/#q=search”的 url 值

这是我当前的代码，用于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 url 值:

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

结果如下:

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，我怎样才能删除具有相同值的每个对象？对象不相等，但具有相同的 url。

我已经尝试过 NSPredicate 并使用更多的 for 循环来遍历并找到匹配的对象，但我总是留下 2 个或更多具有相同属性的相同对象。

最佳答案

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];

关于ios - 如何删除所有具有相同属性值但在 NSMutableArray 中有一个的对象，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/18817136/