Create a NSArray with a specific value of the items of another NSArray.

NSArray+ExtractValuesAsArray.h

@interface NSArray (ExtractValuesAsArray)
/** Creates a new NSArray with the specific value of the items of another array. Ensure that the items of the array are KVC compliant since a key path is used to gather the values.
 */
+(NSArray*)arrayWithValuesOfArrayItems:(NSArray*)array keyPath:(NSString*)keyPath;
@end

NSArray+ExtractValuesAsArray.m

#import "NSArray+ExtractValuesAsArray.h"

@implementation NSArray (ExtractValuesAsArray)
+(NSArray*)arrayWithValuesOfArrayItems:(NSArray *)array keyPath:(NSString *)keyPath {
    NSMutableArray *values = [NSMutableArray arrayWithCapacity:array.count];
    
    for (id item in array) {
        id value = [item valueForKeyPath:keyPath];
        if(value != nil) [values addObject:value];
    }
    
    return [NSArray arrayWithArray:values];
}
@end