Category for NSString that can turn an array of strings into a list with comas and an and at the end.

NSString+ArrayWriter.h

//
//  NSString+ArrayWriter.h
//  Attributed String Creator
//
//  Created by Mark Bridges on 15/10/2013.
//  Copyright (c) 2013 Mark Bridges. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface NSString (ArrayWriter)

+ (NSString*)stringWithArray:(NSArray*)array;

@end

NSString+ArrayWriter.m

//
//  NSString+ArrayWriter.m
//  Attributed String Creator
//
//  Created by Mark Bridges on 15/10/2013.
//  Copyright (c) 2013 Mark Bridges. All rights reserved.
//

#import "NSString+ArrayWriter.h"

@implementation NSString (ArrayWriter)

+ (NSString*)stringWithArray:(NSArray*)array{
    if (array.count == 0) {
        return @"";
    }
    else{
        NSMutableString *outputString = [[NSMutableString alloc]init];
        NSMutableArray *mutableArray = [[NSMutableArray alloc]initWithArray:array];
        if (mutableArray.count == 1) {
            [outputString appendString:[mutableArray objectAtIndex:0]];
        }
        else{
            [outputString appendString:[mutableArray objectAtIndex:0]];
            [mutableArray removeObjectAtIndex:0];
            for (NSString *currentString in mutableArray) {
                if (currentString != mutableArray.lastObject) {
                    [outputString appendString:[NSString stringWithFormat:@", %@",currentString]];
                }
                else{
                    [outputString appendString:[NSString stringWithFormat:@" and %@.",currentString]];
                }
            }
        }
        return outputString;
    }
}

@end