Linq，选择值+-一个值

Question

I need to do a select on a product table. The product has a column called ZipCode I need to get alle the products from a specific zipcode, and the 5 zipcode higher and lower than the selected zipcode

so if i have the zipcode 51235 i need the products from 5 higher zipcodes and lower zipcodes, is this possible with linq?

Hope someone can help

Answer 1

Maybe something like:

var zip = 51235;
context.Products.Where(p => p.ZipCode >= zip - 5 && p.ZipCode <= zip +5); 

Or like this:

var zip = 51235;
var products = from p in context.Products
where p.ZipCode >= zip -5 && p.ZipCode <= zip + 5
select p;

UPDATE:

If you want to do it all in one statement you could do it like this:

        var products = Products.Where(p1 => 
                Products.Select(p2 => p2.ZipCode)
                        .Distinct()
                        .Where(p3 => p3 >= zipCode)
                        .Take(4)
                        .Union(
                            Products.Select(p4 => p4.ZipCode)
                            .Distinct()
                            .Where(p5 => p5 < zipCode)
                            .Take(3)
                        ).Contains(p1.ZipCode)
                );

But it might be easier to split it up into different statements to keep it more readable.

Answer 2

To get products between zipcode-5 and zipcode+5

container.Products.Where(w => (w.ZipCode > zipCode - 5) && (w.ZipCode < zipCode + 5));

To get products have their zipcodes exactly equals to zipcode +/- 5 and current zipcode.

container.Products.Where(w => (w.ZipCode == zipCode - 5) || (w.ZipCode == zipCode + 5) || (w.ZipCode == zipCode + 5));

Answer 3

You can use,

var collectionEqualToZipCode = SourceCollection.Where(source=> source.Zip == SelectedZip);

int lessZipCodesTaken = 0;
int greaterZipCodesCountTaken = 0;
var collectionlessthanOrGreaterthanZipCode = SourceCollection.TakeWhile(source => 
(source.Zip < SelectedZip && lessZipCodesTaken++ < 5) ||
(source.Zip > SelectedZip && greaterZipCodesCountTaken ++ < 5));
FinalCOllection.AddRange(collectionEqualToZipCode);
FinalCOllection.AddRange(collectionlessthanOrGreaterthanZipCode );