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Scala Linq alternative

I'm trying to re-write an application from .net to Scala, mainly for practice and I've come across this Linq expression that I don't know how to work with. linq is also foreign to me so I'm a little bit out of my depth.
private void DeleteItems(AmazonSimpleDB client, IEnumerable<string> itemNames)
{
var deleteableItems = from n in itemNames select new DeleteableItem()
{
ItemName = n
}
}
I'm looking at some other answers using maps but so far have been unsuccessful, thank you for any help.

It will look something like this:
var deleteableItems = itemNames.map(n -> new DeleteableItem(ItemName = n))
Note that your DeleteableItem should have constructor with ItemName parameter.

Best Linq Syntax for To Create List for JQuery Autocomplete

I'm trying to create a list of strings (on a controller method for use as JSON that is consumed by a JQuery Autocomplete on the client). Is there a way to reduce these six or seven lines to two lines? In other words I want the first line to create the IEnumerable of strings.
Also is there a way of not using the custom comparer - all it does is compare strings (on the CompanyMeasureName field).
public JsonResult GetMyMeasureNameList(string term)
{
//I've defined a custom comparer called NameComparer on the MyMeasure Object
IEnumerable<MyMeasure> interList =
MyMeasure.Distinct(new MyMeasure.NameComparer())
.Where(cmo => cmo.CompanyMeasureName
.ToLower()
.Contains(term.ToLower()));
List<string> retList = new List<string>();
foreach (var cmo in interList.ToList())
{
CompanyMeasure c = (CompanyMeasure)cmo;
retList.Add(c.CompanyMeasureName);
}
return Json(retList, JsonRequestBehavior.AllowGet);
}
Thanks in advance

The following solves part of the problem (as usual I came up with the answer 5 seconds after posting the question). However I'd still like to be able to not use a custom comparer as it seems pretty pointless.
IEnumerable<MyMeasure> interList =
MyMeasure.Distinct(new MyMeasure.NameComparer())
.Where(cmo => cmo.CompanyMeasureName
.ToLower()
.Contains(term.ToLower())).Select(m => m.CompanyMeasure);

C# equivalent of Lambda

I'm trying to convert some JS into C# and i got to this piece but cant figure out what a C# equivalent would be. Hoping someone can point me in the right direction?
I just need help with the contents of these two functions. The $iterator is coded in another spot but im guessing that the C# version of the following code doesnt need it. If you need me to add it, i can.
The context these functions are being called is:
var centers = Lambda.array(Lambda.map(this.hexes,function(hex) {
return me.hexToCenter(hex);
}));
And the functions are:
var Lambda = function() { }
Lambda.array = function(it) {
var a = new Array();
var $it0 = $iterator(it)();
while( $it0.hasNext() ) {
var i = $it0.next();
a.push(i);
}
return a;
}
Lambda.map = function(it,f) {
var l = new List();
var $it0 = $iterator(it)();
while( $it0.hasNext() ) {
var x = $it0.next();
l.add(f(x));
}
return l;
}

You don't really need your own map and array methods. There is already the same functionality available, you just have to add using System.Linq; at the top of your file and you'll be able to use both Select, which is a projection method and ToArray which created an array from your collection. They are both extension methods set on IEnumerable<T>, so you can use them on almost any collection.
var centers = hexes.Select(x => me.hexToCenter(x)).ToArray();
is an equivalent of you JavaScript code:
var centers = Lambda.array(Lambda.map(this.hexes,function(hex) {
return me.hexToCenter(hex);
}));

This looks like a fairly simple C# lambda:
var centers = this.hexes.Select(hex => me.hexToCenter(hex)).ToList();
Select and ToList extension methods are provided by LINQ - you need to add using System.Linq to use them.

You probably want to go the LINQ route here.
Your map is equivalent to LINQ's Select, e.g.
var centers = this.hexes.Select(hex => me.hexToCenter(hex)).ToArray();
The expression hex => me.hexToCenter(hex) is a lambda expression in C#, which Select uses to project this.hexes into your desired form.
ToArray() is equivalent to your Lambda.array call.
101 LINQ Samples in C# is a great resource for examples on using LINQ.
note most of the 101 samples use the query syntax as opposed to the functional syntax I've used above. They are roughly equivalent for simple cases, but being comfortable with the functional syntax shouldn't be a problem for you, coming from JS background.

Linq to SQL: Equivalent of Array.SequenceEqual

Let's say I have this method:
public T GetByID(object[] pKeys)
{
DbQuery<T> dbq = mContext.GetDbSet<T>();
return dbq.SingleOrDefault(ent => ent.PrimaryKey.SequenceEqual(pKeys));
}
ent.PrimaryKey is an object[].
Of course, this doesn't work because of the SequenceEqual(). I could maybe use Contains but this would not preserve order: {1, 2} is NOT equal to {2, 1}.
I could also use AsEnumerable() first and then use some logics but that would load the whole table in memory, which is unacceptable.
Is there a way to achieve this?
Edit
I've made the method generic. Because that's what it really is and it makes more sens with the primary key being an array.
I also point out that the goal of the method here could be achieved with mContext.GetDbSet().Find(pKeys). This, however, complicates the use of dbq.Include(property) or mContext.Entry(wanted).Collection(property).Load() for parent.child properties which is another matter not related to the question.

Without reproducible code it is a little tough to test any particular solution, but the first thing that came to my mind (and compiled/tested in notepad) is
public T GetByID(object[] pKeys)
{
DbQuery<T> dbq = mContext.GetDbSet<T>();
for (var i = 0; i < pKeys.length; i++)
{
dbq = dbq.Where(ent => ent.PrimaryKey[i] == pKeys[i]);
}
return dbq.SingleOrDefault();
}

Linq-to-SQL: Combining (OR'ing) multiple "Contains" filters?

I'm having some trouble figuring out the best way to do this, and I would appreciate any help.
Basically, I'm setting up a filter that allows the user to look at a history of audit items associated with an arbitrary "filter" of usernames.
The datasource is a SQL Server data base, so I'm taking the IQueryable "source" (either a direct table reference from the db context object, or perhaps an IQueryable that's resulted from additional queries), applying the WHERE filter, and then returning the resultant IQueryable object....but I'm a little stumped as to how to perform OR using this approach.
I've considered going the route of Expressions because I know how to OR those, but I haven't been able to figure out quite how to do that with a "Contains" type evaluation, so I'm currently using a UNION, but I'm afraid this might have negative impact on performance, and I'm wondering if it may not give me exactly what I need if other filters (in addition to user name filtering shown here) are added in an arbirary order.
Here is my sample code:
public override IQueryable<X> ApplyFilter<X>(IQueryable<X> source)
{
// Take allowed values...
List<string> searchStrings = new List<string>();
// <SNIP> (This just populates my list of search strings)
IQueryable<X> oReturn = null;
// Step through each iteration, and perform a 'LIKE %value%' query
string[] searchArray = searchStrings.ToArray();
for (int i = 0; i < searchArray.Length; i++)
{
string value = searchArray[i];
if (i == 0)
// For first step, perform direct WHERE
oReturn = source.Where(x => x.Username.Contains(value));
else
// For additional steps, perform UNION on WHERE
oReturn = oReturn.Union(source.Where(x => x.Username.Contains(value)));
}
return oReturn ?? source;
}
This feels like the wrong way to do things, but it does seem to work, so my question is first, is there a better way to do this? Also, is there a way to do a 'Contains' or 'Like' with Expressions?
(Editted to correct my code: In rolling back to working state in order to post it, I apparently didn't roll back quite far enough :) )
=============================================
ETA: Per the solution given, here is my new code (in case anyone reading this is interested):
public override IQueryable<X> ApplyFilter<X>(IQueryable<X> source)
{
List<string> searchStrings = new List<string>(AllowedValues);
// <SNIP> build collection of search values
string[] searchArray = searchStrings.ToArray();
Expression<Func<X, bool>> expression = PredicateBuilder.False<X>();
for (int i = 0; i < searchArray.Length; i++)
{
string value = searchArray[i];
expression = expression.Or(x => x.Username.Contains(value));
}
return source.Where(expression);
}
(One caveat I noticed: Following the PredicateBuilder's example, an empty collection of search strings will return false (false || value1 || ... ), whereas in my original version, I was assuming an empty list should just coallesce to the unfiltered source. As I thought about it more, the new version seems to make more sense for my needs, so I adopted that)
=============================================

You can use the PredicateBuilder from the LINQkit to dynamically construct your query.