Create list using properties in other list

Question

I have a list of objects containing project name and owners of the project something like this:

[
    {
        project_name:"abc",
        project_duration:"2 weeks",
        contactInfo: [
          {
            name:"john"
          },
          {
            name:"ron"
          },
        ]
    },
    {
        project_name:"def",
        project_duration:"4 weeks",
        contactInfo: [{
            name:"steve"
        }]
    },
    {
        project_name:"xyz",
        project_duration:"9 weeks",
        contactInfo: [{
            name:"john"
        }]
    }
]

How to create a list containing projects for each user from the above list?

[
    {
        name: "john",
        projects:[
            {
                project_name:"abc"
            },
            {
                project_name:"xyz"
            }

        ]   
    }
]

Answer 1

Group your object based on the property Name value.
Then Select the new object:
- The Name is the grouping key.
- The sublist is just a projection from the old object.

data.GroupBy(x => x.contactInfo.name)
    .Select(g =>
        new Result
        {
            name = g.Key,
            projects =
                g.Select(x => new Project_t2
                {
                    project_name = x.project_name,
                    projec_name = x.project_duration
                }).ToList()
        })
        .ToList();

Live Demo