I have a List with n elements. Before I can use the items I must group them so 1,2,3,4 goes into one group and 4,5,6,7 goes into the next group ... n
my current c# code is:
List<List<Job>> groupedJobs = AlotOfcSharpCode(unGroupedJobs);
A have the feeling that all that can be placed with something like
var groupedJobs = unGroupedJobs.SelectMany().GroupBy().SomeOtherLinq
My basic problem is to iterate over the source list and take every 4 element so 1,2,3,4 goes into one group and 4,5,6,7 goes into the next group using linq.
This is my input:
List<Job> JobList = new List<Job>();
JobList.Add( new Job { JobID = 1, } );
JobList.Add( new Job { JobID = 2, } );
JobList.Add( new Job { JobID = 3, } );
JobList.Add( new Job { JobID = 4, } );
JobList.Add( new Job { JobID = 5, } );
JobList.Add( new Job { JobID = 6, } );
JobList.Add( new Job { JobID = 7, } );
JobList.Add( new Job { JobID = 8, } );
JobList.Add( new Job { JobID = 9, } );
JobList.Add( new Job { JobID = 10, } );
My desired outcome is a structure like
List<List<Job>> Groups = List<List<Job>>();
List<Job> group = new List<Job>();
JobList.Add( new Job { JobID = 1, } );
JobList.Add( new Job { JobID = 2, } );
JobList.Add( new Job { JobID = 3, } );
JobList.Add( new Job { JobID = 4, } );
group = new List<Job>();
JobList.Add( new Job { JobID = 5, } );
JobList.Add( new Job { JobID = 6, } );
JobList.Add( new Job { JobID = 7, } );
JobList.Add( new Job { JobID = 8, } );
group = new List<Job>();
JobList.Add( new Job { JobID = 9, } );
JobList.Add( new Job { JobID = 10, } );
The usage of this grouping is that I need to iterate each group and do stuff.
List<Job> allJobs = stateStorage.Value.Jobs;
var groupedJobs = GroupJobs(allJobs);
foreach (var group in groupedJobs)
{
var doSomething = new DoSomething(group);
}
return something;
}
private static IEnumerable<IEnumerable<Job>> GroupJobs(IEnumerable<Job> allJobs)
{
var groupsIndex = new List<List<Job>>();
var counter = 0;
var group = new List<Job>();
foreach (var job in allJobs)
{
if (counter == 4)
{
groupsIndex.Add(group);
group = new List<Job>();
}
group.Add(job);
counter++;
}
return groupsIndex;
}
You can use the following group function:
JobList.GroupBy(item => (item.JobID - 1) / 4)
Group function is integer division - so values 1 - 4 will receive group value 0, values 5 - 8 will have group value 1 and so on. Looks like this is what you are looking for.
May be this could Help.
Source:
public class Job
{
public int JobID { get; set; }
public static Job[] GetJobs()
{
var jobList = new[] {
new Job { JobID = 1 },
new Job { JobID = 2},
new Job { JobID = 3},
new Job { JobID = 4},
new Job { JobID = 5},
new Job { JobID = 6},
new Job { JobID = 7},
new Job { JobID = 8},
new Job { JobID = 9},
new Job { JobID = 10}
};
return jobList;
}
public override string ToString()
{
return $"Job {{ JobID={JobID} }}";
}
}
Group Query Using Linq:
//Data Source
var source = Job.GetJobs();
//Query Creation
var query = from index in Enumerable.Range(0, source.Length)
group source[index] by index / 4;
//Query Execution
foreach (var item in query)
{
Console.WriteLine($"Group : {item.Key}");
item.ToList().ForEach(it => Console.WriteLine(it.ToString()));
}
Console.ReadLine();
Expected Ouput:
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