通过对具有匹配 ID 号的对象进行分组来重建 NSArray？
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【中文标题】通过对具有匹配 ID 号的对象进行分组来重建 NSArray？【英文标题】：Rebuild an NSArray by grouping objects that have matching id numbers? 【发布时间】：2013-03-13 01:37:40 【问题描述】：我有一个 NSArray，数组中的每个对象都有一个 groupId 和一个名称。每个对象都是唯一的，但有许多具有相同的 groupId。有没有办法可以将数组拆开并重建它，以便将名称分组到具有相应 groubId 的单个对象中？这是数组当前的样子：
2013-03-12 20:50:05.572 appName[4102:702] the array: (
groupId = 1;
name = "Dan";
,
groupId = 1;
name = "Matt";
,
groupId = 2;
name = "Steve";
,
groupId = 2;
name = "Mike";
,
groupId = 3;
name = "John";
,
groupId = 4;
name = "Kevin";
)
这是我想要的样子：
2013-03-12 20:50:05.572 appName[4102:702] the array: (
groupId = 1;
name1 = "Dan";
name2 = "Matt";
,
groupId = 2;
name1 = "Steve";
name2 = "Mike";
,
groupId = 3;
name = "John";
,
groupId = 4;
name = "Kevin";
)
编辑： 我已经尝试过很多次但都失败了，大多数都是这样的（草率的娱乐，但给出一个想法）：
int idNum = 0;
for (NSDictionary *arrObj in tempArr)
NSString *check1 = [NSString stringWithFormat:@"%@",[arrObj valueForKey:@"groupId"]];
NSString *check2 = [NSString stringWithFormat:@"%@",[[newDict valueForKey:@"groupId"]];
if (check1 == check2)
NSString *nameStr = [NSString stringWithFormat:@"name_%d",idNum];
[newDict setValue:[arrObj valueForKey:@"name"] forKey:nameStr];
else
[newDict setValue:arrObj forKey:@"object"];
idNum++;
【问题讨论】：
【参考方案1】：NSArray *array = @[@@"groupId" : @"1", @"name" : @"matt",
@@"groupId" : @"2", @"name" : @"john",
@@"groupId" : @"3", @"name" : @"steve",
@@"groupId" : @"4", @"name" : @"alice",
@@"groupId" : @"1", @"name" : @"bill",
@@"groupId" : @"2", @"name" : @"bob",
@@"groupId" : @"3", @"name" : @"jack",
@@"groupId" : @"4", @"name" : @"dan",
@@"groupId" : @"1", @"name" : @"kevin",
@@"groupId" : @"2", @"name" : @"mike",
@@"groupId" : @"3", @"name" : @"daniel",
];
NSMutableArray *resultArray = [NSMutableArray new];
NSArray *groups = [array valueForKeyPath:@"@distinctUnionOfObjects.groupId"];
for (NSString *groupId in groups)
NSMutableDictionary *entry = [NSMutableDictionary new];
[entry setObject:groupId forKey:@"groupId"];
NSArray *groupNames = [array filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"groupId = %@", groupId]];
for (int i = 0; i < groupNames.count; i++)
NSString *name = [[groupNames objectAtIndex:i] objectForKey:@"name"];
[entry setObject:name forKey:[NSString stringWithFormat:@"name%d", i + 1]];
[resultArray addObject:entry];
NSLog(@"%@", resultArray);
输出：
(
groupId = 3;
name1 = steve;
name2 = jack;
name3 = daniel;
,
groupId = 4;
name1 = alice;
name2 = dan;
,
groupId = 1;
name1 = matt;
name2 = bill;
name3 = kevin;
,
groupId = 2;
name1 = john;
name2 = bob;
name3 = mike;
)
【讨论】：
【参考方案2】：这需要 NSArrays 的 NSDictionary。没有快速而优雅的方法 - 您必须滚动浏览源代码。
NSMutableDictionary *d = [NSMutableDictionary dictionaryWithCapacity:10]; //Or use alloc/init
for(SomeObject o in appname) //What's the type of objects? you tell me
NSObject *ID = [o objectForKey: @"groupId"];
NSMutableArray *a = [d objectForKey: ID];
if(a == nil)
a = [NSMutableArray arrayWithCapacity: 10];
[d setObject:a forKey: ID];
[a addObject: [o objectForKey: @"name"]];
编辑：编辑为不假定密钥的数据类型。
【讨论】：
NSString *ID = [NSNumber numberWithInt: [o objectForKey: @"groupId"]]; numberWithInt 将int 作为参数并返回NSNumber。您提供一个id 参数并分配给NSString。【参考方案3】：
这与 Seva 的回答类似，但可以在 NSArray 上添加为类别方法：
/// @return A dictionary of NSMutableArrays
- (NSDictionary *)abc_groupIntoDictionary:(id<NSCopying>(^)(id object))keyFromObjectCallback
NSParameterAssert(keyFromObjectCallback);
NSMutableDictionary *result = [NSMutableDictionary dictionary];
for (id object in self)
id<NSCopying> key = keyFromObjectCallback(object);
NSMutableArray *array = [result objectForKey:key];
if (array == nil)
array = [NSMutableArray new];
[result setObject:array forKey:key];
[array addObject:object];
return [result copy];
你可以像这样使用它：
NSDictionary *groups = [people abc_groupIntoDictionary:^id<NSCopying>(NSDictionary *person)
return person[@"groupId"];
];
这与原始答案不完全相同，因为它将人员字典保留为数组中的值，但您可以从中读取 name 属性。
【讨论】：
【参考方案4】：为我的菜鸟们快速实现 Sergery 的回答。
class People: NSObject
var groupId: String
var name : String
init(groupId: String, name: String)
self.groupId = groupId
self.name = name
let matt = People(groupId: "1", name: "matt")
let john = People(groupId: "2", name: "john")
let steve = People(groupId: "3", name: "steve")
let alice = People(groupId: "4", name: "alice")
let bill = People(groupId: "1", name: "bill")
let bob = People(groupId: "2", name: "bob")
let jack = People(groupId: "3", name: "jack")
let dan = People(groupId: "4", name: "dan")
let kevin = People(groupId: "1", name: "kevin")
let mike = People(groupId: "2", name: "mike")
let daniel = People(groupId: "3", name: "daniel")
let arrayOfPeople = NSArray(objects: matt, john, steve, alice, bill, bob, jack, dan, kevin, mike, daniel)
var resultArray = NSMutableArray()
let groups = arrayOfPeople.valueForKeyPath("@distinctUnionOfObjects.groupId") as [String]
for groupId in groups
var entry = NSMutableDictionary()
entry.setObject(groupId, forKey: "groupId")
let predicate = NSPredicate(format: "groupId = %@", argumentArray: [groupId])
var groupNames = arrayOfPeople.filteredArrayUsingPredicate(predicate)
for i in 0..<groupNames.count
let people = groupNames[i] as People
let name = people.name
entry.setObject(name, forKey: ("name\(i)"))
resultArray.addObject(entry)
println(resultArray)
注意 valueForKeyPath 中的 @ 符号。这让我有点绊倒:)
【讨论】：
【参考方案5】：下面的代码将重建一个 NSArray，方法是根据该数组中每个字典中的任何匹配键对对象进行分组
//only to a take unique keys. (key order should be maintained)
NSMutableArray *aMutableArray = [[NSMutableArray alloc]init];
NSMutableDictionary *dictFromArray = [NSMutableDictionary dictionary];
for (NSDictionary *eachDict in arrOriginal)
//Collecting all unique key in order of initial array
NSString *eachKey = [eachDict objectForKey:@"roomType"];
if (![aMutableArray containsObject:eachKey])
[aMutableArray addObject:eachKey];
NSMutableArray *tmp = [grouped objectForKey:key];
tmp = [dictFromArray objectForKey:eachKey];
if (!tmp)
tmp = [NSMutableArray array];
[dictFromArray setObject:tmp forKey:eachKey];
[tmp addObject:eachDict];
//NSLog(@"dictFromArray %@",dictFromArray);
//NSLog(@"Unique Keys :: %@",aMutableArray);
//再次从字典转换为数组...
self.finalArray = [[NSMutableArray alloc]init];
for (NSString *uniqueKey in aMutableArray)
NSDictionary *aUniqueKeyDict = @@"groupKey":uniqueKey,@"featureValues":[dictFromArray objectForKey:uniqueKey];
[self.finalArray addObject:aUniqueKeyDict];
希望对你有帮助..
【讨论】：
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