选择同一集合中不重复的重复项

Question

（已编辑）

这是我的代码，其中包含我正在使用的集合的示例： 这就是我写myProducts1 和myProducts1 是嵌套集合时的意思

List<MyProducts> myProducts1= {
new MyProducts{id = 1, Name = "product1", isExcl= true},
new MyProducts{id = 2, Name = "product2", isExcl= false},
new MyProducts{id = 3, Name = "product3", isExcl= true},
new MyProducts{id = 4, Name = "product4", isExcl= false}
}
List<MyProducts> myProducts2= {
new MyProducts{id = 5, Name = "product5", isExcl= true},
new MyProducts{id = 6, Name = "product6", isExcl= false}
}
IEnumerable<SelectedProductRequest> selectedProducts = {
new SelectedProductRequest {id = 1, Name = "product1", Price = 23},
new SelectedProductRequest {id = 1, Name = "product1", Price = 44},
new SelectedProductRequest {id = 2, Name = "product2", Price = 11},
new SelectedProductRequest {id = 6, Name = "product6", Price = 34},
}

List<CategoryProduct> productsWithCategories = {
{CategoryName= "Category1", categoryProduct = myProducts1 },
{CategoryName= "Category2", categoryProduct = myProducts2 }
}

这是我的第一个代码：

IEnumerable<SelectedProductViewModel> products1 = 
.GroupBy(categoryProduct => categoryProduct .CategoryName)
                .Select(categoryProduct => new ProductCategoryViewModel(
                    categoryProduct .Key,
                    categoryProduct 
.Select(product => new SelectedProductViewModel(
                            product.Name,
                            selectedProducts.FirstOrDefault(selectedProduct => selectedProduct.id== product.id)?.Price ?? 0,
                            product.IsExclusive))
                        .OrderByDescending(product => product.id)))

这是我的第二个代码：

IEnumerable<SelectedProductViewModel> products2 = 
.GroupBy(categoryProduct => categoryProduct .CategoryName)
                .Select(categoryProduct => new ProductCategoryViewModel(
                    categoryProduct .Key,
                    categoryProduct
.Join(contractSelectedProducts, product => product.id, selected => selected.id, (product, selected) =>
                            new SelectedProductViewModel(
                            product.Name,
                            selected?.Price ?? 0,
                            product.IsExclusive))

我用这些代码得到的结果：

products1= {"Category1",{
new SelectedProductRequest {id = 1, Name = "product1", Price = 23, IsExclusive = true},
new SelectedProductRequest {id = 2, Name = "product2", Price = 11, IsExclusive = false},
new SelectedProductRequest {id = 3, Name = "product3", Price = 0, IsExclusive = true},
new SelectedProductRequest {id = 4, Name = "product4", Price = 0, IsExclusive = false}
},
"Category2", {new SelectedProductRequest {id = 5, Name = "product5", Price = 0, IsExclusive = true},
new SelectedProductRequest {id = 6, Name = "product6", Price = 34, IsExclusive = false}}

products2= {"Category1",{
new SelectedProductRequest {id = 1, Name = "product1", Price = 23, IsExclusive = true},
new SelectedProductRequest {id = 1, Name = "product1", Price = 44, IsExclusive = true},
new SelectedProductRequest {id = 2, Name = "product2", Price = 11, IsExclusive = false}
}},
"Category2", {new SelectedProductRequest {id = 6, Name = "product6", Price = 34, IsExclusive = false}

但是我想要达到的结果是这样的：

products= {"Category1",{
new SelectedProductRequest {id = 1, Name = "product1", Price = 23, IsExclusive = true},
new SelectedProductRequest {id = 1, Name = "product1", Price = 44, IsExclusive = true},
new SelectedProductRequest {id = 2, Name = "product2", Price = 11, IsExclusive = false},
new SelectedProductRequest {id = 3, Name = "product3", Price = 0, IsExclusive = true},
new SelectedProductRequest {id = 4, Name = "product4", Price = 0, IsExclusive = false}
}},
"Category2",{
{new SelectedProductRequest {id = 5, Name = "product5", Price = 0, IsExclusive = true},
{new SelectedProductRequest {id = 6, Name = "product6", Price = 34, IsExclusive = false}
}

（修改后的代码）

我的问题：如何在不使用products1 和products2 的情况下实现此结果？或者我怎样才能以更好的方式做到这一点？

Answer 1

根据评论更新

解决方案一

我将最后一个 Linq 查询更改为：

List<ProductCategory> mergedList = products1
    // concat products2 with products1
    .Concat(products2)
        // group by category name
        .GroupBy(x => x.CategoryName)
            //dictionay(categoryName, list of SelectedProductRequests)
            .ToDictionary(key => key, value => value.SelectMany(x => x.SelectedProductRequests)
                 .GroupBy(x => new { x.id, x.Name, x.Price, x.IsExclusive })
                // take the first in grouped element
                .Select(x => x.First())
                //convert to SelectedProductRequest
                .Select(x => new SelectedProductRequest { id = x.id, Name = x.Name, Price = x.Price, IsExclusive = x.IsExclusive })
                .OrderBy(x => x.id)//order by id
                .ToList())
            .Select(x => new ProductCategory { CategoryName = x.Key.Key, SelectedProductRequests = x.Value })
            .ToList();

解决方案 2

如果我理解您的需求，您需要构建productsWithCategories 以通过一个linq 请求获得预期结果，然后使用GroupJoin 而不是Join 检查以下命题：

IEnumerable<ProductCategoryViewModel> result = productsWithCategories
    .Select(x => new ProductCategoryViewModel
    {
        CategoryName = x.CategoryName,
        SelectedProductViewModels = x.categoryProduct
            .GroupJoin(selectedProducts, prd => prd.id, sel => sel.id,
                (prd, sel) => sel != null && sel.Any() ?
                sel.Select(y =>
                    new SelectedProductViewModel
                    {
                        id = prd.id,
                        isExcl = prd.isExcl,
                        Name = prd.Name,
                        Price = y.Price
                    }).ToList() :
                    new List<SelectedProductViewModel>
                    {
                        new SelectedProductViewModel
                        {
                            id = prd.id,
                            isExcl = prd.isExcl,
                            Name = prd.Name,
                            Price = 0
                        }
                    })
                    .SelectMany(z => z)
                    .ToList()
    });

希望能帮你解决问题

Answer 2

你可以使用Concat方法加入数组：

var selectedProductsMapped = selectedProducts.Select(s => new SelectedProductRequest
{
    id = s.id,
    Name = s.Name,
    Price = s.Price,
    isExclusive = myProducts.Where(p => p.id == s.id).FirstOrDefault().isExclusive
});

var exlcludedProducts = myProducts.Where(p => !selectedProducts.Any(sp => sp.id == p.id))
    .Select(s => new SelectedProductRequest
    {
         id = s.id,
         Name = s.Name,
         Price = 0                
    });

var result = selectedProductsMapped.Concat(exlcludedProducts);

一个例子：

var selectedProducts = new List<SelectedProductRequest> {
     new SelectedProductRequest {id = 1, Name = "product1", Price = 23},
     new SelectedProductRequest {id = 1, Name = "product1", Price = 44},
     new SelectedProductRequest {id = 2, Name = "product2", Price = 11}
};

var myProducts = new List<MyProducts> {
    new MyProducts{id = 1, Name = "product1", isExclusive= true},
    new MyProducts{id = 2, Name = "product2", isExclusive= false},
    new MyProducts{id = 3, Name = "product3", isExclusive= true},
    new MyProducts{id = 4, Name = "product4", isExclusive= false}
};


var selectedProductsMapped = selectedProducts.Select(s => new SelectedProductRequest
{
    id = s.id,
    Name = s.Name,
    Price = s.Price,
    isExclusive = myProducts.Where(p => p.id == s.id).FirstOrDefault().isExclusive
});

var exlcludedProducts = myProducts.Where(p => !selectedProducts.Any(sp => sp.id == p.id))
    .Select(s => new SelectedProductRequest
    {
         id = s.id,
         Name = s.Name,
         Price = 0                
    });

var result = selectedProductsMapped.Concat(exlcludedProducts);

Answer 3

您可以使用 Linq 的 Union() 生成 products1 和 products2 的集合。您将需要实现SelectedProductRequest 的GetHashCode()。

products = products1.Union(products2);

Try it Online!

将此添加到SelectedProductRequest：

public class SelectedProductRequest : IEquatable<SelectedProductRequest>
{
    public int id {get;set;}
    public string Name {get;set;}
    public int Price {get;set;}
    public bool IsExclusive {get;set;}

    public bool Equals(SelectedProductRequest other) => other is null
        && this.id == other.id
        && this.Name == other.Name
        && this.Price == other.Price
        && this.IsExclusive == other.IsExclusive;

    public override bool Equals(object obj) => Equals(obj as SelectedProductRequest);
    public override int GetHashCode() => (id, Name, Price, IsExclusive).GetHashCode();
}