CODEWITHSUNDEEP
c#linq
KnightsOfTheRoun
KnightsOfTheRoun

Reputation: 155

Compare two lists for Max value within a parameter using linq

I have a list of Field objects, with a parameter of (string)Name and (int)Size.

I also have a list of File objects, each containing a list of Field objects, in which some of them may appear in the overarching Field objects.

I need to go through all the Field objects, and find the max value of all possible File-Field objects.

I could do this with nesting 3? for loops, but I wanted to see if this is possible in linq.

List<fieldobject> mainfields;
List<fileobject> files;

within the fileobject class:

List<fieldobject> fields;

Basic concept in for loops would be:

foreach (fieldobject field in mainfields)
    foreach (fileobject file in files)
        foreach (fieldobject fileField in file.fields)
            if (field.name == fileField.name)
                field.size = math.max(field.size,fileField.size);

I can replace that if and assignment with a linq, but I was hoping to get rid of most/all of the for loops. Any help is greatly appreciated.

Upvotes: 0

Views: 1601

Answers (2)

Jonathan Applebaum
Jonathan Applebaum

Reputation: 5986

If i understand correctly file.fields is an internal list of fileobject inside fileobject object so you need to use the SelectMany extension method:

foreach (fileobject field in mainfields)
{
    field.size = files.SelectMany(x => x.fields)
   .Where(y => y.name == field.name).Select(m => m.size).Max();
}

Upvotes: 1

DiskJunky
DiskJunky

Reputation: 4971

You could have something like;

foreach (fieldobject field in mainfields)
{
    int maxFileSize = files.Where(f => f.name == field.name)
                           .Select(f => f.size)
                           .Max();
    if (field.size < maxFileSize)
    {
         field.size = maxFileSize;
    }
}

Upvotes: 0

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