Handy NSArray category method for splitting an NSArray

NSArray+JTArraySection.h

// ARC

@interface NSArray (JTArraySection)

- (NSDictionary *)dictionaryBySectionKeyPath:(NSString *)keyPath;
- (NSArray *)arrayBySectionKeyPath:(NSString *)keyPath;

@end

NSArray+JTArraySection.m

#import "NSArray+JTArraySection.h"

@implementation NSArray (JTArraySection)

- (NSDictionary *)dictionaryBySectionKeyPath:(NSString *)keyPath {
    NSMutableDictionary *newDict = [NSMutableDictionary dictionary];
    
    [self enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        NSString *name = [obj valueForKey:keyPath];
        
        NSMutableArray *array = [newDict objectForKey:name];
        
        if ( ! array) {
            array = [NSMutableArray array];
            [newDict setObject:array forKey:name];
        }
        
        [array addObject:obj];
        
    }];
    
    return newDict;
}

- (NSArray *)arrayBySectionKeyPath:(NSString *)keyPath {
    return [[self dictionaryBySectionKeyPath:keyPath] allValues];
}

@end

NSArray+JTArraySplit.h

//
//  NSArray+JTArraySplit.h
//
//  Created by james on 10/18/11.
//

#import <Foundation/Foundation.h>

@interface NSArray (JTArraySplit)

+ (NSArray *)splitArray:(NSArray *)targetArray componentsPerSegment:(NSUInteger)componentsCount;

@end

NSArray+JTArraySplit.m

//
//  NSArray+JTArraySplit.m
//
//  Created by james on 10/18/11.
//

#import "NSArray+JTArraySplit.h"

@implementation NSArray (JTArraySplit)

+ (NSArray *)splitArray:(NSArray *)targetArray componentsPerSegment:(NSUInteger)componentsCount {
    NSMutableArray *splitedArray = [NSMutableArray array];

    NSUInteger targetArrayCount = [targetArray count];
    
    if (targetArrayCount > 0) {
        int index = 0;
        while (index < targetArrayCount) {
            int length = MIN(targetArrayCount - index, componentsCount);
            NSArray *subArray = [targetArray subarrayWithRange:NSMakeRange(index, length)];
            [splitedArray addObject:subArray];
            index = index+length;
        }
        return splitedArray;
    } else {
        // no objects inside targetArray, so just return empty array
        return splitedArray;
    }
}

@end