Lambda Statement

Question

I am wondering if there is a better way of accomplishing this;

I have an object - one of the property is a Dictionary. I have a set of comma separated values. I need to filter the Dictionary and get only those elements where the Dictionary value matches at least one of the values

This is what I have tried but is there is a shorter way of doing this?

Just to explain: filterValue is the list of values(E.g. "4,5')

List<string> vals = new List<string>();
vals.AddRange(filterValue.Split(new char[]{','}));
List<T> bindingEntities = entities.Where(
 e => {
 foreach(KeyValuePair<string, object> kvp in e.ExtraProperties)
 {
 if(vals.Contains(kvp.Value.ToString()))
 return true;
 }
 return false;
 }).ToList();

• juharr: Well, you don't need to put the results of the Split into a list and you can just do .Split(',').
• myermian: Depending on how many values are in the filterValue, it might be more worthwhile to use a HashSet<T> instead of a List<T>. In fact, arrays support the Contains() method all the same, so there is no point in creating a List<T> at all either: var vals = filtervalue.Split(new char[] {','});.

Answer 1

You can use Any function:

List<string> vals = new List<string>();
vals.AddRange(filterValue.Split(new char[] { ',' }));
var bindingEntities = entities.Where(
 e => e.ExtraProperties.Any(
 kvp => vals.Contains(kvp.Value.ToString()))).ToList();

• Rupesh Saini: Too Good! Short and clean!
• Yuval Itzchakov: You can even make it shorter if you drop the List<string> declaration and use the string[] returned from string.Split.
• Slugart: I think the parentheses around ToString() need to be fixed so that it will compile
• Yuval Itzchakov: @Slugart Nope, they're fine.
• Slugart: Really, Any() returns a bool and there's ToList() method on bool - just try to compile it.

Answer 2

List<string> vals = new List<string>();
vals.AddRange(filterValue.Split(new char[]{','}));
List<T> bindingEntities = entities.Where(
 e => e.ExtraProperties.Values.Any(
 val => vals.Contains(val.ToString())))
 .ToList();

or

List<string> vals = new List<string>();
vals.AddRange(filterValue.Split(new char[]{','}));
List<T> bindingEntities = from e in entities
 from val in e.ExtraProperties.Values
 where vals.Contains(val.ToString())
 select e;

• Vano Maisuradze: ExtraProperties does not have Values property
• Slugart: ExtraProperties is Dictionary right? msdn.microsoft.com/en-us/library/ekcfxy3x(v=vs.110).aspx
• Slugart: @VanoMaisuradze am I mistaken?
• Vano Maisuradze: I forgot that it was dictionary. So the answer is no :)
• Vano Maisuradze: Well if you think that this downvote is mine, then take my upvote )) good luck

Answer 3

Is there a reason aren't you just querying the dictionary object?

var result = filterValue.Where(d => d.Value.Contains(val.ToString()).ToList();

Now you have the dictionary objects that contain the filter so you can work with them instead of going through the extra step of constructing a bunch of string arrays that you don't really need.