remove object from NSArray - ios

How can I remove an object from a reversed NSArray.
Currently I have a NSMutableArray, then I reverse it with
NSArray* reversedCalEvents = [[calEvents reverseObjectEnumerator] allObjects];
now I need to remove at item from reversedCalEvents or calEvents and automatically refresh the table the array is displayed in based on conditions.
i.e.
if(someInt == someOtherInt){
remove object at index 0
}
How can I do this? I cannot get it to work.

Here's a more functional approach using Key-Value Coding:
#implementation NSArray (Additions)
- (instancetype)arrayByRemovingObject:(id)object {
return [self filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:#"SELF != %#", object]];
}
#end

You will need a mutable array in order to remove an object. Try creating reversedCalEvents with mutableCopy.
NSMutableArray *reversedCalEvents = [[calEvents reverseObjectEnumerator] allObjects] mutableCopy];
if (someInt == someOtherInt)
{
[reversedCalEvents removeObject:object];
}

NSArray is not editable, so that you cannot modify it. You can copy that array to NSMutableArray and remove objects from it. And finally reassign the values of the NSMutableArray to your NSArray.
From here you will get a better idea...
NSArray + remove item from array

First you should read up on the NSMutableArray class itself to familiarize yourself with it.
Second, this question should show you an easy way to remove the objects from your NSMutableArray instance.
Third, you can cause the UITableView to refresh by sending it the reloadData message.

you can try this:-
NSMutableArray* reversedCalEvents = [[[calEvents reverseObjectEnumerator] allObjects] mutableCopy];
[reversedCalEvents removeLastObject];

Related

can't add objects of an array in another array

i am trying to show selected cell checkmark when user is offline,but the array is not adding another array object, kindly help me
1.appDelegate.SelectedIDArray saving selected cell
2.buildingObject.selectedIDString saving checked cell index coma separated
//first i am removing all objects from array
[appDelegate.SelectedIDArray removeAllObjects];
//then i am adding string values in array(e.g 3,2,7)
NSMutableArray *tempArray = (NSMutableArray*)[buildingObject.selectedIDString componentsSeparatedByString:#","];
//now adding tempArray array objects in appDelegate.SelectedIDArray
[appDelegate.SelectedIDArray addObjectsFromArray:tempArray];
//now showing count of added object in appDelegate.SelectedIDArray
txtID.text=[NSString stringWithFormat:#"%zd of 23 selected",appDelegate.SelectedIDArray.count];
by saying offline, you mean app is terminated, then if you didn't save your array in NSUserDefaults it is nil already. then you should initialize it. if this is not the case another problem may be with appDelegate:
AppDelegate *appDelegate = (AppDelegate *)[UIApplication sharedApplication].delegate;
NSString *vals = #"1,2,3,4,5,6,7,8";
NSMutableArray *tempArray = [[vals componentsSeparatedByString:#","] mutableCopy];
if (!appDelegate.SelectedIDArray) {
appDelegate.SelectedIDArray = [NSMutableArray new];
}
else
{
[appDelegate.SelectedIDArray removeAllObjects];
}
[appDelegate.SelectedIDArray addObjectsFromArray:tempArray];
NSLog(#"%#", appDelegate.SelectedIDArray);
I've took sample test case similar to your code:
NSString *str1 = #"1,2,3,4,5,6,7,8,9";
NSMutableArray *tempArray = (NSMutableArray*)[str1 componentsSeparatedByString:#","];
NSMutableArray *arr = [NSMutableArray array];
[arr addObjectsFromArray:tempArray];
NSLog(#"%#",arr);
Its working fine for me. Make sure appDelegate.SelectedIDArray is NSMutableArray. Or if you want fresh array simply use
appDelegate.SelectedIDArray = [NSMutableArray arraywitharray:tempArr];
Hope this helps.
I hope you did not forget to alloc appDelegate.SelectedIDArray.
Hello buddy please try this
NSArray *tempArray = [buildingObject.selectedIDString componentsSeparatedByString:#","];
[appDelegate setSelectedIDArray:[tempArray mutableCopy]];
if it didnot work then possibly one of your array is empty.Please check
use it, it will fix if you are using the non arc
appDelegate.SelectedIDArray = [tempArray retain];

Objective-C: Remove duplicates efficiently from large data structures

I have an object containing an array of NSNumbers (indexes) and an array of NSDictionaries (indexesTitles) corresponding to indexes, containing some info.
I have to call a method for each object.index and associate object.indexTitles to the returning results, saving them into a single array.
At the end of it, I want to remove indexes duplicates, preserving the associated indextTitles in an efficient way, because I'm working with large arrays.
NSMutableArray *resultArray = [NSMutableArray array];
NSMutableArray *titlesArray = [NSMutableArray array];
for(NSNumber *index in object.indexes)
{
NSArray *resultsIndexArray = [self methodThatReturnsAnArray];
NSString *indexTitleDictionary = [object.indexesTitles objectAtIndex:i];
for(NSNumber *resultId in resultsIndexArray)
{
[titlesArray addObject:indexDictionary];
[resultArray addObject:resultId];
}
i++;
}
[fullResultsArray addObject:titlesArray];
[fullResultsArray addObject:resultArray];
I've found that the most efficient way to remove duplicates is using an
NSOrderedSet like this:
NSOrderedSet *orderedSet = [NSOrderedSet orderedSetWithArray:resultArray];
resultArray = [orderedSet.array mutableCopy];
How can I remove the corresponding entries in titlesArray? how can I preserve the association?
I've also tried to use a NSDictionary like {resultId, titleDictionary} and storing them into an array, but I haven't found a efficient way to remove dictionaries with the same result, they are all too slow.
Any suggestion?
It is not completely clear to me what your problem is, maybe this will help:
A good way to remove duplicates is not to add them in the first place, replace:
for(NSNumber *resultId in resultsIndexArray)
{
[titlesArray addObject:indexDictionary];
[resultArray addObject:resultId];
}
with:
for(NSNumber *resultId in resultsIndexArray)
{
// only add if resultId not already in resultArray
if( ![resultArray containsObject:resultId] )
{
[titlesArray addObject:indexDictionary];
[resultArray addObject:resultId];
}
}
The containsObject: call requires a linear search, if your data set is large you might wish to change resultArray to an NSMutableSet and titlesArray to an NSMutableDictionary mapping from resultId to indexDictionary values.
HTH

How to Make Array of Float Data Type in ios

I want to make array of float type.
Anybody can help me?
NSArray *arrOfFloat = [[[NSArray alloc]initWithObjects:[12.2, 23.44], nil]];
But i want to make array dynamically.
But i want to make array dynamically.
This means you'll have to use an NSMutableArray.
NSMutableArray *array = [[NSMutableArray alloc] init];
[array addObject:#1.1];
[array addObject:#2.2];
...
You also can't add primitives to an array. You'll need to add objects. Notice the # I added before the numbers. This creates number literals.
If you have the floats you want to add as variables, you can auto boxing like this:
[array addObject:#(myFloatVariable)];
Use NSMutableArray class instead of a NSArray (this is a subclass of it), this way, within your code, you will be able to call :
NSMutableArray *yourArray = [NSMutableArray new];
[yourArray addObject:#(1.0f)];
NSArraycan only store objects, so in your case you would have to store your float as NSNumber. If you want to store objects dynamically, thus adding or removing them to an NSArray you have to use the mutable object type called NSMutableArray.
You'll need to wrap your float's in an NSNumber:
[NSNumber numberWithFloat:12.2];
If you're dynamically adding elements to an array, you need to use NSMutableArray.
NSMutableArray *array = [NSMutableArray array];
[array addObject:[NSNumber numberWithFloat:12.2]];
You can use NSMutableArray for example named arrOfFloat and add this :
[arrOfFloat addObject:[NSNumber numberWithFloat:3.5]];
[arrOfFloat addObject:[NSNumber numberWithFloat:23.44]];
Hope, It will may helpful to you.

How can I move the values in NSMutableArray to NSArray

I have an array of recommendedcar IDs, and another array of allcar IDs. From this, I have to take the recommendedcar images. First, I check whether the recommended carid is in my allcar id; if it is, I select the corresponding car images, and store them into NSArray.
This is the code I am using.
for (int i=0;i<[listOfCarId count];i++) {
for (int j=0;j<[_allCarID count];j++) {
tempAllCarId=[_allCarID objectAtIndex:j];
tempRecommendedCarId=[listOfCarId objectAtIndex:i];
if ([tempRecommendedCarId isEqualToString:tempAllCarId]) {
_recommendedCarImage=[_allCarImages objectAtIndex:j];
NSLog(#"finalImage%#",_recommendedCarImage);
}
}
}
_recommendedcarImage is NSMUtableArray; I want a NSArray. How can I convert it to a NSArray?
How can i replace the "_recommendedCarImage " with an NSArray?? Currently _recommendedCarImage is a mutable array.
Polymorphism. Since NSMutableArray is a subclass of NSArray, you can use it anywhere an NSArray is expected. You don't have to do anything.
Now its working,What i did is , I just copy the contents of Mutable array to NSarray
recommendedArray=[_recommendedCarImage copy];
An NSMutableArray is an NSArray already (as it's a subclass of NSArray), still you can do:
NSArray *array = [NSArray arrayWithArray:mutableArray];

How to add object at first index of NSArray

I want to add #"ALL ITEMS" object at the first index of NSARRAY.
Initially the Array has 10 objects. After adding, the array should contains 11 objects.
you can't modify NSArray for inserting and adding. you need to use NSMutableArray. If you want to insert object at specified index
[array1 insertObject:#"ALL ITEMS" atIndex:0];
In Swift 2.0
array1.insertObject("ALL ITEMS", atIndex: 0)
First of all, NSArray need to be populated when it is initializing. So if you want to add some object at an array then you have to use NSMutableArray. Hope the following code will give you some idea and solution.
NSArray *array = [[NSArray alloc] initWithObjects:#"1",#"2",#"3",#"4",#"5",#"6",#"7",#"8",#"9",#"0", nil];
NSMutableArray *mutableArray = [[NSMutableArray alloc] init];
[mutableArray addObject:#"ALL ITEMS"];
[mutableArray addObjectsFromArray:array];
The addObject method will insert the object as the last element of the NSMutableArray.
I know that we have six answers for insertObject, and one for creating a(n) NSMutableArray array and then calling addObject, but there is also this:
myArray = [#[#"ALL ITEMS"] arrayByAddingObjectsFromArray:myArray];
I haven't profiled either though.
Take a look at the insertObject:atIndex: method of the NSMutableArray class.To add an object to the front of the array, use 0 as the index:
[myMutableArray insertObject:myObject atIndex:0];
NSArray is immutable array you can't modify it in run time. Use NSMutableArray
[array insertObject:#"YourObject" atIndex:0];
NSArray is immutable but you can use insertObject: method of NSMutableArray class
[array insertObject:#"all items" atIndex:0];
As you are allready having 10 objects in your array,and you need to add another item at index 11...so,you must try this.... hope this helps..
NSMutableArray *yourArray = [[NSMutableArray alloc] initWithCapacity:11];
[yourArray insertObject:#"All Items" atIndex:0];
NSArray is not dyanamic to solve your purpose you have to use NSMutableArray. Refer the following method
- (void)insertObject:(id)anObject atIndex:(NSUInteger)index;
Apple documents says NSMutableArray Methods
[temp insertObject:#"all" atIndex:0];
Swift 3:
func addObject(){
var arrayName:[String] = ["Name1", "Name2", "Name3"]
arrayName.insert("Name0", at: 0)
print("---> ",arrayName)
}
Output:
---> ["Name0","Name1", "Name2", "Name3"]

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