LinQ WHERE string.Contains or string.IndexOf?

Question

I need to write something that would give the same result as:

var result = collection.Where( o => o.Name.IndexOf( \"some_string2\" ) != -1 || o.Name.Index         


        

Answer 1

var result = collection.Where(item => stringsToCheck.Any(stringToCheck => 
    item.Name.Contains(stringToCheck)));

Read in English this is: give me all of the items in the collection where, of all of the strings to check one of them is a substring of the string in the collection.

Answer 2

If you want to check whether o.Name contains some string from the stringsToCheck, I would suggest to use LinqKit and build the query with PredicateBuilder.

var predicate = PredicateBuilder.False<TypeOfYourObject>();
var stringsToCheck = someCommaSeparatedStrings.ToLower().Split( ',' ).ToList();

foreach(var str in stringsToCheck)
{
     var tmp = str; 
     predicate = predicate.Or(o=> o.Name.IndexOf(tmp) != -1);
} 
resultQuery = collection.Where(predicate); 

Answer 3

You are checking the collections element o.ToLower() i assume you must check for its name o.Name.ToLower().

Answer 4

If you want to test whether o.Name contains a stringToCheck then:

var result = collection.Where( o => stringsToCheck.Any(a => o.Name.Contains(a)));

If you only need to test for equality, then:

var result = collection.Where( o => stringsToCheck.Contains(o.Name));

Note: if you need to apply case normalisation then ToLower() should be applied accordingly.