split array of objects into groups of 4 - ios - ios

Question

How do you split an array of objects into an array of array of objects?
say I want to split into groups of 4, how do I do that?
[a,b,c,d,e,f,g,h] =>
[a,b] [c,d] [e,f] [g,h]
or maybe if I specify that I want to split into groups of 3, then the result should be
[a,b,c], [d,e,f], [g,h]
it should also work if h doesn't exist.

Answer 1

Try this logic.....
NSArray *arr = [[NSArray alloc]initWithObjects:#"One",#"Two",#"Three",#"Four",#"Five",#"Six",#"Seven",nil];
NSMutableArray *arrNew = [[NSMutableArray alloc]init];
int numberofSubArrs = 3; // change this to check the logic
for (int i=0; i<numberofSubArrs; i++) {
NSMutableArray *arrrr = [[NSMutableArray alloc]init];
[arrNew addObject:arrrr];
}
int m = 0;
for (int k=0; k<[arr count]; k++) {
[[arrNew objectAtIndex:m]addObject:[arr objectAtIndex:k]];
m++;
if (m == numberofSubArrs) {
m=0;
}
}
int g=0;
int p=0;
while(p<[arr count]) {
for (int z=0; z<[[arrNew objectAtIndex:g] count]; z++) {
[[arrNew objectAtIndex:g] replaceObjectAtIndex:z withObject:[arr objectAtIndex:p++]];
}
g++;
}
NSLog(#"Required Array is:%#",[arrNew description]);

Answer 2

Try this as a starting point:
NSArray *array = [NSArray arrayWithObjects:#"a", #"b", #"c", #"d", #"e", #"f", #"g", #"h", nil];
NSMutableArray *manyArrays = [NSMutableArray array];
int numberOfElementsInSubArrays = 2;
int numberOfSubArrays = ceil((float)[array count] / (float)numberOfElementsInSubArrays);
for (int i = 0; i < numberOfSubArrays; i++) {
NSMutableArray *subArray = [NSMutableArray array];
for (int j = 0; j < numberOfElementsInSubArrays; j++) {
if (i*numberOfElementsInSubArrays+j < [array count]) {
NSLog(#"Array: %d Value:%#", i, [array objectAtIndex:i*numberOfElementsInSubArrays+j]);
[subArray addObject:[array objectAtIndex:i*numberOfElementsInSubArrays+j]];
}
}
[manyArrays addObject:subArray];
}

Answer 3

Give this a try.
NSMutableArray *splitted = [NSMutableArray array];
id firstItem, secondItem;
for (NSInteger i=0; i <= [originalArray count]-1; i+=2) {
#try {
firstItem = [originalArray objectAtIndex:i];
secondItem = [originalArray objectAtIndex:i+1];
}
#catch (NSException *exception) {
secondItem = [NSNull null];
}
#finally {
[splitted addObject:#[firstItem,secondItem]];
}
}