Question

I have a Dictionary with an Orders array with amount and orders in it Orders = ("3 White Shirts", "8 White Shirts", "4 blue shorts")

How would I loop through it and add the amount of duplicate orders so that the result string or array would be
Orders = ("11 White Shirts", "4 blue shorts") or myString ="11 White Shirts, 4 blue shorts"

I’m thinking some sort of substring to check if the products are the same but not sure how to capture the correct quantity to add from the duplicate order

Many thanks

Answer 1

Ok here is a way to do this (the shortest one I could think of):

// Assuming that 'orders' is the array in your example
NSMutableDictionary *orderDict = [[NSMutableDictionary alloc] init]; 

for (NSString *order in orders)
{
    // Separate the string into components
    NSMutableArray *components = [[order componentsSeparatedByString:@" "] mutableCopy];

    // Quantity is always the first component
    uint quantity = [[components objectAtIndex:0] intValue];
    [components removeObjectAtIndex:0];

    // The rest of them (rejoined by a space is the actual product)
    NSString *item = [components componentsJoinedByString:@" "];

    // If I haven't got the order then add it to the dict
    // else get the old value, add the new one and put it back to dict
    if (![orderDict valueForKey:item])
        [orderDict setValue:[NSNumber numberWithInt:quantity] forKey:item];
    else{
        uint oldQuantity = [[orderDict valueForKey:item] intValue];
        [orderDict setValue:[NSNumber numberWithInt:(oldQuantity+quantity)] forKey:item];
    }
}

This would give you a dict like this:

{
    "White Shirts" = 11;
    "blue shorts" = 4;
}

So you could iterate over the keys and produce an array of strings like this:

NSMutableArray *results = [[NSMutableArray alloc] initWithCapacity:0];
for (NSString *key in [orderDict allKeys])
{
    [results addObject:[NSString stringWithFormat:@"%@ %@", [orderDict valueForKey:key], key]];
}

Which finally will give you:

(
    "11 White Shirts",
    "4 blue shorts"
) 

PS. Don’t forget to release if you don’t use ARC !