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c#linqstringienumerable
Neil Hodges
Neil Hodges

Reputation: 127

C# Linq where clause .Contains(string[])

Ive been googling for the last few hours to find a solution to my problem but im stumpped. I was wondering if someone could help me out with the following.

I have a Linq query that queries against a DataTable. I have a param of string[] BodyTypes that holds strings like "5,7,11" or "6,7,4" or just "5,"

the Linq i have is:

 var query2 = (from v in query.AsEnumerable()
                              where  (from yy in BodyTypes       
                                      select yy).Contains(v.Header36.ToString())
                              select new
                              {
                                  PartNumber = v.PartNumber,
                                  Position = v.Position,
                                  ImagePath = v.ImagePath,
                                  Supplier = v.Supplier,
                                  Price = v.Price,
                                  RRP = v.RRP,
                                  Stock = v.Stock,
                                  BaseCat = v.BaseCat,
                                  Description = v.Description,
                                  Header36 = v.Header36,
                                  GT_Id = v.GT_Id
                              });

v.Header36 has different values assigned to it per row i.e. "11,7,4,5" or "11,6,7"

My problem is how do i make a match using Linq, i want to match Header36 with anything that is passed in the string[]BodyTypes array like using a wild card or like statement. My problem is also this DataTable is loaded from a 3rd party's webservice, so no SQL backend can be used here. Any suggestions would be greatfully appreciated.

Kind Regards Neil.

Upvotes: 0

Views: 3979

Answers (3)

Jon Skeet
Jon Skeet

Reputation: 1500335

Making it LINQ to Objects actually means it's easier to answer. I think you want something like:

from v in query.AsEnumerable()
let headers = v.Header36.Split(',')
where yy.BodyTypes.Intersect(headers).Any()
select new [...]

Note that your (from yy in BodyTypes select yy) is mostly equivalent to just BodyTypes (at least it will be given the way you're then using it) - you don't need to use a query expression every time you want to do anything.

Here's a slightly more efficient version:

HashSet<String> bodyTypes = new HashSet<String>(yy.BodyTypes);
var query = from v in query.AsEnumerable()
            let headers =  v.Header36.Split(',')
            where bodyTypes.Overlaps(headers)
            select new [...]

Upvotes: 1

Richard Friend
Richard Friend

Reputation: 16018

If i have understood this correct your body time might contain 1,2,3,4 and your Header36 might contain 2,5 and you want to match when an item appears in both delimted strings ?

Change your where clause 

where  (from yy in BodyTypes select yy)
    .Any(bts=> bts.Split(',').Any(bt=> v.Header36.Split(',').Contains(bt)) )

Upvotes: 0

GreyCloud
GreyCloud

Reputation: 3100

try using a regex and the .Any method:

where  (from yy in BodyTypes  
        select yy).Any( y => (new Regex(v.Header36.ToString())).IsMatch(y))

Upvotes: 0

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