IOS：在更新“重复”的属性时合并两个 NSArray

Question

编辑：大量编辑，很抱歉造成混乱！

我目前正在开发一个应用程序，其中我使用两种不同的方法从 JSON WebService 获取 2 个数组。

在第一个数组中，我得到本地库存。在第二个数组中，我得到了供应商库存。

虽然我认为图片会更好地解释：

因此，Web 服务获取了许多商品。数组 1 包含来自本地库存的一些商品，数组 2 包含来自我们供应商的商品，并添加了描述等信息。我想合并两个数组，用供应商库存数组 2 中的项目描述更新我们本地 stock-array1 中的现有项目。

这是我想要实现的一个示例。所有产品都由唯一标识符属性（示例中未提及）标识，并且我已覆盖 isEqual 和 hash 来弥补这一点。如果一个产品有一个相似的 ID，它被认为是相同的。

**Product**

@property id *internalID;
@property id *externalID ;
@property id *localStock;
@property id *supplierStock;
@property id *image;
@property id *productInfo;

现在Webservice 1返回三个产品：

产品 1

*internalID = ABCDEF
*externalID = (null)
*localStock = 15
*supplierStock = (null)
*image = (null)
*productInfo = (null);

产品 2

*internalID = GHIJK
*externalID = (null)
*localStock = 13
*supplierStock = (null)
*image = niceImage.png
*productInfo = @"This Product is Awesome!";

产品 3

*internalID = LMNOP
*externalID = (null)
*localStock = 7
*supplierStock = (null)
*image = (null)
*productInfo = (null);

Webservice 2 返回四个产品，其中两个也在数组 1 中：

产品 1

    *internalID = (null)
    *externalID = 123456
    *localStock = (null)
    *supplierStock = 12
    *image = external_product1image.jpg
    *productInfo = @"This product is also Awesome and in both local stock and supplier stock!";

产品 4

    *internalID = (null)
    *externalID = 23456
    *localStock = (null)
    *supplierStock = 11
    *image = niceImage.png
    *productInfo = @"This Product is Awesome and only available from our supplier!";

产品 3

    *internalID = (null)
    *externalID = 78901
    *localStock = (null)
    *supplierStock = 7
    *image = external)supplierimage.jpg
    *productInfo = @"This product is also Awesome and in both local stock and supplier stock!";

那么mergedArray 应该是这样的：

产品 1

*internalID = ABCDEF
*externalID = 123456
*localStock = 15
*supplierStock = 12
*image = external_product1image.jpg
*productInfo = @"This product is also Awesome and in both local stock and supplier stock!";

//所以 Array 1 中的 Product 1 将其属性与 Array 2 中的 Product 1 合并

产品 2

*internalID = GHIJK
*externalID = (null)
*localStock = 13
*supplierStock = (null)
*image = niceImage.png
*productInfo = @"This Product is Awesome!";

产品 3

*internalID = LMNOP
*externalID = 78901
*localStock = 7
*supplierStock = 7
*image = external)supplierimage.jpg
*productInfo = @"This product is also Awesome and in both local stock and supplier stock!";

产品 4

*internalID = (null)
*externalID = 23456
*localStock = 13
*supplierStock = 11
*image = niceImage.png
*productInfo = @"This Product is Awesome and only available from our supplier!";

这是我使用的代码，但它似乎有时会以某种方式出现故障：

- (void) compareArrays:(id)sender metBreedte:(NSString *)breedte metHoogte:(NSString *)hoogte metDiameter:(NSString *)diameter
{
    NSMutableSet *getBandenSet = [NSMutableSet setWithArray:getBandenArray];      NSUInteger i = 0;

    while (i < [getBandenInfo1Array count]) {
        id getBandenInfo1Object = [getBandenInfo1Array objectAtIndex:i];
        if ([getBandenSet containsObject:getBandenInfo1Object])

        {

            BWBand *getBandenBand = [getBandenSet member:getBandenInfo1Object];

            BWBand *getBandenInfo1Band = getBandenInfo1Object;

            // Do stuff to the Banden (sync)
            getBandenBand.alternatievePrijs = getBandenInfo1Band.alternatievePrijs;
            getBandenBand.itemName = getBandenInfo1Band.itemName;
            getBandenBand.supplierStock = getBandenInfo1Band.supplierStock;
            getBandenBand.grossPrice = getBandenInfo1Band.grossPrice;
            getBandenBand.eancode = getBandenInfo1Band.eancode;
            getBandenBand.EMarked = getBandenInfo1Band.EMarked;
            getBandenBand.garagePrijs = getBandenInfo1Band.garagePrijs;
            getBandenBand.loadIndex = getBandenInfo1Band.loadIndex;
            getBandenBand.brand = getBandenInfo1Band.brand;
            getBandenBand.custPrice = getBandenInfo1Band.custPrice;
            getBandenBand.netPrice = getBandenInfo1Band.netPrice;
            getBandenBand.tyreLabel = getBandenInfo1Band.tyreLabel;
            getBandenBand.TyreLabelFuel = getBandenInfo1Band.TyreLabelFuel;
            getBandenBand.TyreLabelNoise = getBandenInfo1Band.TyreLabelNoise;
            getBandenBand.TyreLabelNoiseLevel = getBandenInfo1Band.TyreLabelNoiseLevel;
            getBandenBand.TyreLabelWet = getBandenInfo1Band.TyreLabelWet;
            getBandenBand.foto = getBandenInfo1Band.foto;
            NSMutableString *string1 = [NSMutableString stringWithString: getBandenBand.colorStock];
            NSString *newString = [string1 substringToIndex:[string1 length]-2];
            NSString *colorStock = [NSString stringWithFormat:@"%@-%@",newString,getBandenInfo1Band.supplierStock];
            getBandenBand.colorStock = colorStock;
           [getBandenSet removeObject:getBandenInfo1Object];
            [getBandenInfo1Array removeObjectIdenticalTo:getBandenInfo1Object];
        } else
        {i++;}

        mergedBandenArray = [NSMutableArray arrayWithArray:[getBandenArray arrayByAddingObjectsFromArray:getBandenInfo1Array]];
       [mergedBandenArray sortUsingDescriptors:
         [NSArray arrayWithObjects:
          [NSSortDescriptor sortDescriptorWithKey:@"colorStock" ascending:NO], [NSSortDescriptor sortDescriptorWithKey:@"brand" ascending:YES], nil]];}

所有这些都可以使用 NSPredicates 完成吗？如果有，怎么做？

提前致谢！

Answer 1

以下算法不需要您为 Product 类覆盖 isEqual 和 hash：

• 首先根据uniqueItemID键升序对两个数组进行排序。
• 然后并行遍历两个数组，并将两个数组中的产品添加或合并到目标数组。

如果两个数组都已排序，则可以通过并行遍历两个数组的单个循环轻松找到匹配和不匹配的产品。

以下代码有望证明这一想法：

NSSortDescriptor *sortByID = [NSSortDescriptor sortDescriptorWithKey:@"uniqueItemID" ascending:YES];
NSArray *sorted1 = [array1 sortedArrayUsingDescriptors:@[sortByID]];
NSArray *sorted2 = [array2 sortedArrayUsingDescriptors:@[sortByID]];

NSUInteger i1 = 0, i2 = 0;
NSMutableArray *combined = [NSMutableArray array];
while (i1 < [sorted1 count] && i2 < [sorted2 count]) {
    Product *p1 = sorted1[i1];
    Product *p2 = sorted2[i2];
    switch ([p1.uniqueItemID compare:p2.uniqueItemID]) {
        case NSOrderedAscending:
            // p1 is in first array, but not in second:
            [combined addObject:p1];
            i1++;
            break;
        case NSOrderedDescending:
            // p2 is in second array, but not in first:
            [combined addObject:p2];
            i2++;
            break;
        case NSOrderedSame:
            // p1, p2 have same ID:
            ... update p1 with values from p2 ...
            [combined addObject:p1];
            i1++, i2++;
            break;
    }
}
// Add remaining products from first array:
while (i1 < [sorted1 count]) {
    [combined addObject:sorted1[i1]];
    i1++;
}
// Add remaining products from second array:
while (i2 < [sorted2 count]) {
    [combined addObject:sorted2[i2]];
    i2++;
}

Answer 2

1)。合并两个数组：

NSMutableSet *set = [NSMutableSet setWithArray:array1]; [设置 addObjectsFromArray:array2]; NSArray *array = [设置所有对象];

2)。在 NSPredicates 的帮助下删除重复项：

1. Filtering Fun with Predicates

2. Hello, NSPredicate

3)。合并和删除重复项：

NSArray *array1, *array2; MSMutableArray *result = [array1 mutableCopy]; for (array2 中的 id 对象) { [结果删除对象：对象]； // 如果已经存在，则删除重复项。 [结果添加对象：对象]； }