从对象数组中删除重复项[重复]

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removing duplicates from array in objective c 8 answers

从目标c 8答案中删除数组中的重复项

ok new to objective c. I have my app going to a web site and pulling company data. Company name address etc. I want to display the state from each company. But I only want one of each state shown. For example if I have CA,CA,CA,AZ,AZ,AZ,NY. I only want to display on my tableview CA,AZ,NY. I am have tried distinctUnionOfObjects, but I think I am using it wrong. any help?

对目标c不熟悉。我让我的应用程序访问网站并提取公司数据。公司名称地址等我想显示各公司的状态。但我只想要显示每个州中的一个。例如,如果我有CA,CA,CA,AZ,AZ,AZ,NY。我只想在我的桌面CA,AZ,NY上显示。我已经尝试过distinctUnionOfObjects,但我认为我错了。任何帮助?

#import "StatesTableViewController.h"

@interface StatesTableViewController ()

@end

@implementation StatesTableViewController

NSArray *companies;


- (void)viewDidLoad {
    [super viewDidLoad];
    NSString *address = @"http://www.Feed";
    NSURL *url = [[NSURL alloc] initWithString:address];

    //laod the data on a background queue..
    //if we were connecting to a an online url then we need it
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        companies = [self readCompanies:url];

        //now that we have the data, reload the table data on the main ui thread
        [self.tableView performSelectorOnMainThread:@selector(reloadData) withObject:nil waitUntilDone:YES];
    });
}


//new code
- (NSArray *)readCompanies:(NSURL *)url {
    //create a nsurlrequest with the given Url
    NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:
                             NSURLRequestReloadIgnoringLocalAndRemoteCacheData timeoutInterval:30.0];

    //get the data
    NSURLResponse *response;
    NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];

    //now create a nsdictionary from the json data
    NSDictionary *jsonDictionary = [NSJSONSerialization JSONObjectWithData:data
                                                                   options:0 error:nil];

    //create a new array to hold the comanies
    NSMutableArray *companies = [[NSMutableArray alloc] init];

    //get an array of dictionaries with the key "company"
    NSArray *array = [jsonDictionary objectForKey:@"companies"];

    //iterate throught the array of dictionaries
    for (NSDictionary *dict in array) {
        //create a new company object with information in the dictionary
        Company *company = [[Company alloc] initWithJSONDictionary:dict];

        //add the Company object to the array
        [companies addObject:company];


    }


    //return the array of Company objects
    return companies;







}
//trying to get 1 state here?  should i create a new array?
//added code to show 1 of each state.   companies array now uniquevalues
//NSArray* uniqueValues = [companies valueForKeyPath:[NSString stringWithFormat:@"distinctUnionOfObjects.%@",@"state"]];

//or
//static NSArray *uniqueValues = nil;
//if (uniqueValues == nil){
//    uniqueValues = [NSArray arrayWithArray:[companies valueForKeyPath:[NSString stringWithFormat:@"distinctUnionOfObjects.%@",@"state"]]];
//}
//or

//companies = [companies valueForKeyPath:@"@distinctUnionOfObjects.state"];

//end added code



- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


#pragma mark -table view controller methods
//change uniqueValue errors to companies

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger) section {
  //    return [uniqueValues count];
    return [companies count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *cellID = @"CellIDState";
    UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:cellID];

    if (cell == nil){
        //single line on table view
        //cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:cellID];
        // dual line on table view
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellID];
    }

     //Company *company = [uniqueValues objectAtIndex:indexPath.row];
    Company *company = [companies objectAtIndex:indexPath.row];

    //cell.textLabel.text = company.company_id;
    cell.textLabel.text = company.state;
    cell.detailTextLabel.text = [NSString stringWithFormat:@"%@",company.companyName];
    //adds cheveron to tableviewl
    [cell setAccessoryType: UITableViewCellAccessoryDisclosureIndicator];

    return cell;
}

#pragma mark - navigation
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{


}


@end

2 个解决方案

#1

Suppose you have a Company object with the following interface:

假设您有一个具有以下界面的Company对象:

@interface Company : NSObject
@property (nonatomic) NSString *name;
@property (nonatomic) NSString *state;
@end

Next, let's say you do the following:

接下来,假设您执行以下操作:

// Creating & adding a few companies
Company *company1 = [Company new];
company1.name = @"Some Company";
company1.state = @"CA";

Company *company2 = [Company new];
company2.name = @"Some Company";
company2.state = @"CA";

Company *company3 = [Company new];
company3.name = @"Some Company";
company3.state = @"CA";

Company *company4 = [Company new];
company4.name = @"Some Company";
company4.state = @"AZ";

Company *company5 = [Company new];
company5.name = @"Some Company";
company5.state = @"AZ";

self.companies = @[company1, company2, company3, company4, company5];

NSArray *uniqueStates = [self.companies valueForKeyPath:@"@distinctUnionOfObjects.state"];
NSSet *uniqueStatesSet = [NSSet setWithArray:[self.companies valueForKey:@"state"]];

The uniqueStates array & uniqueStatesSet set will both contain two objects, @"CA" and @"AZ" (two ways of getting a unique set objects).

uniqueStates数组和uniqueStatesSet集都包含两个对象,@“CA”和@“AZ”(两种获取唯一集合对象的方法)。

#2

NSArray *companies = …;

NSOrderedSet *states = [NSOrderedSet orderedSetWithArray:[companies valueForKey:@"state"]];

If you have an ordered list of unique items, you should use an ordered set to model it.

如果您有唯一项目的有序列表,则应使用有序集对其进行建模。

#1