split NSArray in groups of smaller NSArrays for paging - iphone

Question

I have an NSArray of say 100 NSManagedObjects and I need to split that into an NSArray that contains 10 NSArray objects that each hold 10 of theses NSManagedObjects, how would I accomplish that?
I am going to do some paging and this will work well for me.

Answer 1

How are you getting these NSManagedObjects? If you're using an NSFetchRequest, you may want to keep that around and only get 10 results at a time from it.

Answer 2

Here is my code:
[object splitArrayWithArray:arrayWith100Objects rangeNumber:10];
- (NSArray*) splitArrayWithArray:(NSArray*)rawArray rangeNumber:(int)rangeNumber{
int totalCount = rawArray.count;
int currentIndex = 0;
NSMutableArray* splitArray = [NSMutableArray array];
while (currentIndex<totalCount) {
NSRange range = NSMakeRange(currentIndex, MIN(rangeNumber, totalCount-currentIndex));
NSArray* subArray = [rawArray subarrayWithRange:range];
[splitArray addObject:subArray];
currentIndex +=rangeNumber;
}
return splitArray;
}

Answer 3

Something along these lines should work instead of breaking it into separate arrays
//make a new range for each page
NSRange myRange = NSMakeRange(10, 10);
NSArray * myArray = [NSArray array];
//...pass both into a function
for (int i = myRange.location; i < myRange.location + myRange.length; i++) {
//stuff with the array elements
[[myArray objectAtIndex:i] doSomething];
}

Answer 4

It's no one-liner, but this will split an array into pages:
NSArray *arrayToSplit = ...
int pageSize = 50;
NSMutableArray *arrayOfPages = [NSMutableArray new];
NSRange range = NSMakeRange(0, pageSize);
while (range.location < arrayToSplit.count) {
if (range.location + range.length >= arrayToSplit.count)
range.length = arrayToSplit.count - range.location;
[arrayOfPages addObject:[arrayToSplit objectsAtIndexes:[NSIndexSet indexSetWithIndexesInRange:range]]];
range.location += range.length;
}