LINQ Splitting and group by resulting property - linq

Question

I have an object and one of the properties of the object is a comma delimited list of names e.g.
IList<Audits> auditData = new List<Audits>();
auditData.Add(new Audit
{
Auditors = "Adam West, George Best",
TimeSpent = 7
});
auditData.Add(new Audit
{
Auditors = "Adam West",
TimeSpent = 5
});
auditData.Add(new Audit
{
Auditors = "Adam West, George Best, Elvis Presley",
TimeSpent = 3
});
I'd like to use LINQ to query this data, split the auditors property, group by auditor and total the timespent for each auditor, to give me a list of auditors with time spent against each one e.g.
Adam West 15,
George Best 10,
Elvis Presley 3
Can anyone assist me in doing that? Thanks.

Answer 1

Using lambdas:
var results =
auditData
// Flatten list - to list of individual auditors and time spent
.SelectMany(
audit => audit.Auditors.Split(',').Select(s => s.Trim()),
(audit, auditorName) => new
{
Auditor = auditorName,
TimeSpent = audit.TimeSpent,
})
// Group by auditor name
.GroupBy(a => a.Auditor)
// Sum time spent
.Select(auditorGroup => new
{
Auditor = auditorGroup.Key,
TotalTimeSpent = auditorGroup.Sum(a => a.TimeSpent)
})
.ToList();

Answer 2

This should do what you want:
var query =
from a in auditData
let auditors = a.Auditors.Split(',').Select(s => s.Trim())
from au in auditors
group a.TimeSpent by au into g
select new { Auditor = g.Key, TimeSpent = g.Sum() };

Answer 3

var res = auditData.Select(audit => audit.Auditors.Split(',').ToDictionary(a => a, a => audit.TimeSpent))
.SelectMany(a => a)
.GroupBy(a => a.Key)
.ToDictionary(g => g.Key, s => s.Sum(g => g.Value));
First split the strings and convert to KeyValue pairs. Then flatten the dictionaries into a single one. Then group and sum.