DIctionary of Arrays - iphone

Question

I m doing stuff in which i need sorting as per category.
I have array of objects having objects as
array1 = name,roll number,group name.
array2 = name,roll number,group name.
I want to categorized above array based on same group. I don t want to compare with hard coded group name.
It means i want members with same country name in separate array. Here array count will not be hardcoded. It will create as data is present. My data is as below.
Please suggest me any logic.
Thanks...
Item 0
Student Name ="ABC"; Roll No ="12"; Country ="USA"
Item 1
Student Name ="DEF"; Roll No ="12"; Country ="INDIA"
Item 2
Student Name ="DEF"; Roll No ="12"; Country ="INDIA"
Item 3
Student Name ="DEF"; Roll No ="12"; Country ="USA"

Answer 1

How about just creating a simple class with properties containing these attributes?

Answer 2

Assuming you have a NSArray containing other NSArrays, filled with NSString objects (as your edit suggets), why not writing a simple method ?
Here is an example of method for an object having a property called myItems of type NSArray
// NSArray *myItems, containing your stuff
-(NSArray *)itemsWithCountryName:(NSString *)aCountryName {
NSMutableArray *items = [NSMutableArray arrayWithCapacity:[myItems count]];
NSArray *myItemAsAnArray;
for(myItemAsAnArray in [self myItems]) {
// your edit suggets 2 as the index for the country name
// maybe you can provide a defined constant
if([[myItemAsAnArray objectAtIndex:2] isEqualToString:aCountryName]) {
[items addObject:myItemAsAnArray];
}
}
return items;
}
But maybe you work with dictionaries...
-(NSArray *)itemsWithCountryName:(NSString *)aCountryName {
NSMutableArray *items = [NSMutableArray arrayWithCapacity:[myItems count]];
NSDictionary *myItemAsAnDictionary;
for(myItemAsAnDictionary in [self myItems]) {
// same again for the key
if([[myItemAsAnArray objectForKey:#"Country"] isEqualToString:aCountryName]) {
[items addObject:myItemAsAnArray];
}
}
return items;
}
Good luck !