Alternative of ArrayList in iOS? - ios

Question

I have parsed a JSON that resulted in array of elements. I wish to store it in a an array just like we would add elements dynamically to arraylist and access it later. What is the alternative of ArrayList in case of iOS for adding elements dynamically and retrieving it later. Is there any other unique options available in iOS for storing and retrieving elements dynamically?
Data1:
Reference number: 1241
InvoiceNumber: 1421241
InvoiceDate: 06-FEB-16
Data2:
Reference number: 3241
InvoiceNumber: 12421
InvoiceDate: 06-FEB-16
Above are the two data with unique elements that I got by parsing a json.
In class A , Im adding the following code to store the nsmutablearray in nsuserdefaults,
for (NSUInteger i = 0; i < savecount; i++) {
NSMutableArray *newArray = [[NSMutableArray alloc] init];
[myArrays addObject:newArray];
[newArray addObject:shipmentReferenceNumber];
[[NSUserDefaults standardUserDefaults] setObject:newArray forKey:#"shipmentReferenceNumber "];
}
In class B, Im trying to access it by using the following code but it returns null
NSString *referenceNumber = [[NSUserDefaults standardUserDefaults] stringForKey:#"referenceNumber"];

Answer 1

In objC and swift, An ArrayList is a NSMutableArray
A hash map like functionality (store key value pairs. keys are unique) is offered by NSDictionary

Answer 2

To used Hash Map with NSArray. Used following code.
In Class A while Storing:
NSMutableArray* arrayList = [[NSMutableArray alloc] init];
for (int i=0; i<savecount; i++) {
NSDictionary* innerDict = [NSDictionary dictionaryWithObjectsAndKeys:your_referenceNo,#"referenceNo",your_InvoiceNumber,#"invoiceNumber",your_InvoiceDate,#"invoiceDate", nil];
[arrayList addObject:innerDict];
}
NSData *encodedObject = [NSKeyedArchiver archivedDataWithRootObject:arrayList];
[[NSUserDefaults standardUserDefaults] setObject:encodedObject forKey:#"data"];
In Class B while retraving:
NSData* data = [[NSUserDefaults standardUserDefaults] objectForKey:#"data"];
NSMutableArray* arrayList = [NSKeyedUnarchiver unarchiveObjectWithData:data];
NSLog(#"Reference No : %#",arrayList[0][#"referenceNo"]);
Edit: to dynamic access into arraylist
for(int i=0; i<[arrayList count];i++){
NSLog(#"Reference No : %#",arrayList[i][#"referenceNo"]);
}
Thanks

Answer 3

NSMutableArray can be used if the array is editable, else an NSArray.

Answer 4

Forgive me if I misunderstand what you are trying to achieve, but I would consider creating a Data model object:
#interface Data : NSObject
#property (nonatomic) NSInteger referenceNumber;
#property (nonatomic) NSInteger invoiceNumber;
#property (strong, nonatomic) NSString *invoiceDate;
#end
You could then create an array of data objects:
#property (strong, nonatomic) NSMutableArray <Data *> *dataArray;

Answer 5

Here a data struct, which dynamically increased and gets by index, basically, it is a normal linked list class, with a dynamic array inside to provide getting data by index, it duplicates the space, but you may delete the linked list after updating the array, see the code:
struct LinkedNode
{
long data;
LinkedNode* next;
};
class LinkedList
{
public:
LinkedList();
~LinkedList();
LinkedNode* head;
long Count;
long * Data;
void add(long data);
void update();
//long get(long index);
};
LinkedList::LinkedList(){
this->Count = 0;
this->head = NULL;
}
LinkedList::~LinkedList(){
LinkedNode * temp;
while(head){
temp= this->head ;
head = head->next;
delete temp;
}
if (Data)
delete [] Data; Data=NULL;
}
void LinkedList::add (long data){
LinkedNode * node = new LinkedNode();
node->data = data;
node->next = this->head;
this->head = node;
this->Count++;}
void LinkedList::update(){
this->Data= new long[this->Count];
long i = 0;
LinkedNode * node =this->head;
while(node){
this->Data[i]=node->data;
node = node->next;
i++;
}
}
If you use this, please refer to my work https://www.liebertpub.com/doi/10.1089/big.2018.0064