Filtering Nested array with linq

Question

I have an array like this coming from API response and I want to filter by nested property products to returns product with only id 11

  "assets": [
    {
      "name": "abc",
      "products": [
        {
          "id": "11",
          "status": true
        },
        {
          "id": "14",
          "status": null
        }
      ]
    },
    {
      "name": "xyz",
      "products": [
        {
          "id": "11",
          "status": true
        },
        {
          "id": "28",
          "status": null
        }
      ]
    },
    {
      "name": "123",
      "products": [
        {
          "id": "48",
          "status": null
        }
      ]
    },
    {
      "name": "456",
      "products": [
        {
          "id": "11",
          "status": true
        }
      ]
    }
  ]

the resulting output should look like this,

  "assets": [
    {
      "name": "abc",
      "products": [
        {
          "id": "11",
          "status": true
        }
      ]
    },
    {
      "name": "xyz",
      "products": [
        {
          "id": "11",
          "status": true
        }
      ]
    },
    {
      "name": "123",
      "products": []
    },
    {
      "name": "456",
      "products": [
        {
          "id": "11",
          "status": true
        }
      ]
    }
  ]

I'm trying to return filter output with the C# LINQ method. but, getting an error when filtering a nested array with the following method

"Cannot convert lambda expression to intended delegate type because some of the return types in the block are not implicitly convertible to the delegate return type"

assets.Select(asset => asset.products.Where(product => product.id == "11")).ToArray();

I'm getting this error "Cannot convert lambda expression to intended delegate type because some of the return types in the block are not implicitly convertible to the delegate return type" — Sanjay V
– Sanjay V, Commented Jun 9, 2020 at 0:01
You need to put the error in your question, not in a comment. — Dour High Arch
– Dour High Arch, Commented Jun 10, 2020 at 17:42

Pavel Anikhouski · Accepted Answer · 2020-06-09 09:35:50Z

1

You can just remove all items from every products array, whose id doesn't equal 11. Parse JSON to JObject, iterate over assets array, find products with id different from 11 and remove them form original array

var json = JObject.Parse(jsonString);

foreach (var asset in json["assets"])
{
    var productsArray = asset["products"] as JArray;
    if (productsArray == null)
        continue;

    var productsToRemove = productsArray
        .Where(o => o?["id"]?.Value<int>() != 11)
        .ToList();

    foreach (var product in productsToRemove) 
        productsArray.Remove(product);
}

Console.WriteLine(json);

edited Jun 9, 2020 at 9:35

answered Jun 9, 2020 at 9:29

Pavel Anikhouski

23.6k12 gold badges66 silver badges81 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Pavel Anikhouski Over a year ago

@SanjayV Does it answer your question, do you need more details or information?

Pirasanna Ravi · Accepted Answer · 2020-06-09 01:55:23Z

Instead of Select and Applying a, Where try to remove the Products that you do not want.

Following is a sample code.

class Program
    {
        static void Main(string[] args)
        {

            var json = @"
                {
                    'assets': [
                    {
                    'name': 'abc',
                    'products': [
                        {
                        'id': '11',
                        'status': true
                        },
                        {
                        'id': '14',
                        'status': null
                        }
                    ]
                    },
                    {
                    'name': 'xyz',
                    'products': [
                        {
                        'id': '11',
                        'status': true
                        },
                        {
                        'id': '28',
                        'status': null
                        }
                    ]
                    },
                    {
                    'name': '123',
                    'products': [
                        {
                        'id': '48',
                        'status': null
                        }
                    ]
                    },
                    {
                    'name': '456',
                    'products': [
                        {
                        'id': '11',
                        'status': true
                        }
                    ]
                    }
                ]}";

            var root = JsonConvert.DeserializeObject<Root>(json);
            var assets = root.Assets;
            assets.ForEach(a =>
            {
                a.Products.RemoveAll(p => p.Id != 11);
            });
        }
    }

    public partial class Root
    {
        [JsonProperty("assets")]
        public List<Asset> Assets { get; set; }
    }

    public partial class Asset
    {
        [JsonProperty("name")]
        public string Name { get; set; }

        [JsonProperty("products")]
        public List<Product> Products { get; set; }
    }

    public partial class Product
    {
        [JsonProperty("id")]
        public long Id { get; set; }

        [JsonProperty("status")]
        public bool? Status { get; set; }
    }

Jawad · Accepted Answer · 2020-06-09 05:05:10Z

To filter the list, you will need to create a new list with products whose ID == YourId. Following linq query does the necessary steps to create the list you want.

Filter out any assets that dont have any product with ID == 11. This is necessary to skip nulls in the new list that will be generated (Where statement)
Create a collection / list of new assets that only have the products whose ID == 11 (Select statement)

var list = assets.Where(x => x.Products.Where(y => y.Id.Equals("11")).Count() > 0)
                    .Select(asset => { 
                        return new Asset() { 
                            Name = asset.Name, 
                            Products = asset.Products.Where(x => x.Id == "11").ToList() 
                            }; 
                    }).ToList();

// Create the RootObject that holds a list of all the arrays if you want.
Rootobject newAssetCollection = new Rootobject() { Assets = list };

Below is the Json that was printed

Console.WriteLine(JsonConvert.SerializeObject(newAssetCollection, Formatting.Indented));

{
  "assets": [
    {
      "name": "abc",
      "products": [
        {
          "id": "11",
          "status": true
        }
      ]
    },
    {
      "name": "xyz",
      "products": [
        {
          "id": "11",
          "status": true
        }
      ]
    },
    {
      "name": "456",
      "products": [
        {
          "id": "11",
          "status": true
        }
      ]
    }
  ]
}

Collectives™ on Stack Overflow

Filtering Nested array with linq

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related