How to restructure an Object in C# using LINQ? - json

Question

I have a data set as follows:
[
{
"Id": 1,
"Country": "Uruguay",
"Name": "Foo",
"Status": "Completed",
},
{
"Id": 2,
"Country": "Uruguay",
"Name": "Foo",
"Status": "Completed",
},
{
"Id": 3,
"Country": "Germany",
"Name": "Foo",
"Status": "Completed",
},
]
I want to transform and sort it by Country so that it looks as follows:
[
{
"Country": "Uruguay",
"Details": [
{
"Id": 1,
"Name": "Foo",
"Status": "Completed",
},
{
"Id": 2,
"Name": "Foo",
"Status": "Completed",
},
],
},
{
"Country": "Germany",
"Details": [
{
"Id": 3,
"Name": "Foo",
"Status": "Completed",
},
],
},
],
These are the classes in C#:
public class Countries {
public int Id { get; set; }
public string Country { get; set; }
public string Name { get; set; }
public string Status { get; set; }
}
public class Details {
public int Id { get; set; }
public string Name { get; set; }
public string Status { get; set; }
}
public class CountryList {
public string Country { get; set; }
public List<Details> Details { get; set; }
}
Some of what I have tried looks as followed:
var foo = countries
.GroupBy(x => new Details { Id = x.Id, Name = x.Name, Status = x.Status })
.Select( y => new CountryList
{
// Country = y.Key.
}
var foo = countries
.GroupBy(x => x.Country)
.Select( y => new CountryList
{
// Country = y.Key.
Details = y.GroupBy(a => new Details
{
Id = a.Id,
Name = a.Name,
Status = a.Status
}).ToList()
}
I am having trouble working out how to use LINQ to solve this. I have done a handful of GroupBy operations in the past, but I wasn't able to work this one out. How do I transform my dataset into the desired result?

Answer 1

You do not need second GroupBy
var foo = countries
.GroupBy(x => x.Country)
.Select(y => new CountryList
{
Country = y.Key,
Details = y.Select(a => new Details
{
Id = a.Id,
Name = a.Name,
Status = a.Status
}).ToList()
};

Answer 2

You can take advantage of the .GroupBy() overload that lets you define a resultSelector to create your CountryLists and populate their Details:
var countries = new List<Countries>
{
new() { Id = 1, Country = "Uruguay", Name = "Foo", Status = "Completed" },
new() { Id = 2, Country = "Uruguay", Name = "Foo", Status = "Completed" },
new() { Id = 3, Country = "Germany", Name = "Foo", Status = "Completed" },
};
List<CountryList> countryList = countries
.GroupBy(
c => c.Country,
( country, matches ) => new CountryList()
{
Country = country,
Details = matches.Select(match => new Details
{
Id = match.Id,
Name = match.Name,
Status = match.Status
}).ToList()
})
.ToList();
, ( country, matches ) => new CountryList() { ... } being the resultSelector.
Example fiddle here.

Answer 3

try this
var orig = JsonConvert.DeserializeObject<List<Countries>>(json);
List<CountryList> countries = orig.GroupBy(o => o.Country)
.Select(x => new CountryList {
Country = x.Key,
Details = x.Select(o => new Details {Id=o.Id,Name=o.Name,Status=o.Status} ).ToList()
}).ToList();