Linq to filter nested list

Question

Ok, I wrote below `LINQ to Entities` query (close enough to my c# query showing below) ``` var itemss = filteredstudents .Where(x => x.SubjectTypes.Any(y => y.SubjectItem.Any(z => z.Name == value1))).ToList(); ``` still little problem because when SubjectItem type has two element and one of them match with `value1`. it still returns both. It should return only matching record. I know the problem is with Any but not sure `Any` to replace with what? ``` foreach (StudentDTO student in filteredstudents) { bool valid = true; foreach (SubjectTypes subjectType in student.SubjectTypes) { string value1 = subjectType.SubjectItem.Select(x => x.value1).First(); Guid StId = _context.Items.Where(x => x.Name == value1).FirstOrDefault(); if (StId != null) valid = true; else { valid = false; _log("create log"); } } if (valid) filteredstudentsWithUnits.Add(student); } ``` Sample Input ``` {"Name":"ABC", "Age":12, ,"SubjectTypes": [ {"Id":"1","Description":""Description","SubjectItem":[{"Id":"1","Marks"…

Accepted Answer

You could filter the list first using `.Where` and then use `.Select` to project to a new collection that contains only the data you want. Something like the following may work:

```
var itemss = filteredstudents
    .Where(s => s.SubjectTypes.Any(st => st.SubjectItem.Any(si => si.Name  == value1)))
    .Select(s => new StudentDTO
    {
        Name = s.Name,
        Age = s.Age,
        SubjectTypes = s.SubjectTypes.Where(st => st.SubjectItem.Any(si => si.Name  == value1))
            .Select(st => new SubjectType
            {
                Id = st.Id,
                Description = st.Description,
                SubjectItem = st.SubjectItem.Where(si => si.Name == value1).ToList()
            }).ToList()
    })
    .ToList();
```

Linq to filter nested list

Solution

Problem