C# Remove duplicated objects from list and increase first-CodePudding

I have an list of objects => class Example { int quantity; string name; string comment; } and I want to remove all duplicates and increase the quantity by the number of duplicates that have the same name and comment.

Example:

[
    {quantity: 1, name: "Hello", comment: "Hello there"},
    {quantity: 2, name: "Bye", comment: "Good bye"},
    {quantity: 1, name: "Hi", comment: "Hi there"},
    {quantity: 1, name: "Hello", comment: "Hello there"},
    {quantity: 1, name: "Bye", comment: "Good bye"},
]

and the result it should be:

[
    {quantity: 2, name: "Hello", comment: "Hello there"},
    {quantity: 3, name: "Bye", comment: "Good bye"},
    {quantity: 1, name: "Hi", comment: "Hi there"}
]

CodePudding user response：

Here's a simple solution, which gives you the answer in the List tata but you can do .ToArray() if you wish.

    public class Example 
    { 
        public int quantity; 
        public string name; 
        public string comment; 
    }

    Example[] toto = new Example[]
    {
        new Example
        {
            quantity = 1,
            name = "Hello",
            comment = "Hello there"
        },
        new Example
        {
            quantity = 2,
            name = "Bye",
            comment = "Good bye"
        },
        new Example
        {
            quantity = 1,
            name = "Hi",
            comment = "Hi there"
        },
        new Example
        {
            quantity = 1,
            name = "Hello",
            comment = "Hello there"
        },
         new Example
        {
            quantity = 1,
            name = "Bye",
            comment = "Good bye"
        }
    };

    List<Example> tata = new List<Example>();
    foreach (Example exa in toto)
    {
        bool found = false;
        foreach (Example exb in tata)
        {
            if (exb.name == exa.name && exb.comment == exa.comment)
            {
                exb.quantity  = exa.quantity;
                found = true;
                break;
            }
        }
        if (!found)
        {
            tata.Add(exa);
        }
    }

A good exercise would be to LINQ that!

CodePudding user response：

Here's what I'd do:

Example[] before = new Example[]
{
    new Example { Quantity = 1, Name = "Hello", Comment = "Hello there" },
    new Example { Quantity = 2, Name = "Bye", Comment = "Good bye" },
    new Example { Quantity = 1, Name = "Hi", Comment = "Hi there" },
    new Example { Quantity = 1, Name = "Hello", Comment = "Hello there" },
    new Example { Quantity = 1, Name = "Bye", Comment = "Good bye" },
};

Example[] after =
    before
        .GroupBy(x => new { x.Name, x.Comment }, x => x.Quantity)
        .Select(x => new Example { Quantity = x.Sum(), Name = x.Key.Name, Comment = x.Key.Comment })
        .ToArray();

That gives: