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Sorting by nested Dictionary value?

var userInformation = new Dictionary<string, Dictionary<string, int>>();
I need a new dictionary that equals this one, but is sorted first by key then by the value's value. I tried:
var resultInformation = userInformation.OrderBy(k => k.Key).ThenBy(v => v.Value.OrderByDescending(x => x.Value));
I tried a couple of other methods but no effect.

Dictionaries aren't sorted, but you can easily produce a list/collection of the items in your dictionaries, like so:
var resultInformation = from outer in userInformation
from inner in outer.Value
let data = new { Outer = outer.Key, Inner = inner.Key, Value = inner.Value }
orderby data.Outer, data.Inner, data.Value
select data;
Or the query syntax equivalent:
var resultInformation = userInformation
.SelectMany(i => i.Value, (key, inner) => new { Outer = key, Inner = inner.Key, Value = inner.Value})
.OrderBy(e => e.Outer)
.ThenBy(e => e.Inner)
.ThenBy(e => e.Value);
Update: Based on your clarifying comment, I think what you really want is something more like this:
var resultInformation =
from student in userInformation
orderby student.Key
select new
{
studentId = student.Key,
courses =
from courseScore in student.Value
orderby courseScore.Value descending
select new {
course = courseScore.Key,
score = courseScore.Value
}
};

How to get value from Dictionary<string,object>

I have a dictionary for which I want to retrieve results matching to those of list
here is what I have done so far
Dictionary<string, Dictionary<string, int>> SomeDictionary = new Dictionary<string, Dictionary<string, int>>();
List<int> MyList = new List<int>()
{
2,3,4,5
};
Dictionary<string, int> internalDictionary = new Dictionary<string, int>();
internalDictionary.Add("two", 2);
internalDictionary.Add("three", 3);
internalDictionary.Add("four", 4);
internalDictionary.Add("five", 5);
Dictionary<string, int> AnotherDictionary = new Dictionary<string, int>();
AnotherDictionary.Add("six", 6);
AnotherDictionary.Add("three", 3);
AnotherDictionary.Add("seven", 7);
SomeDictionary.Add("Dictionary1", internalDictionary);
SomeDictionary.Add("Dictionary2", AnotherDictionary);
var res = from l in MyList
select(from q in
(from p in
(from s in SomeDictionary
select s)
select p) where q.Value.Equals(l) select q);
The value returned is null. what am i Missing ?
I need matching KeyValuePair where value matches internal dictionary values.

Explanation:
Select Many to combine all internal dictionaries into All In One dictionary.
List and SelectMany are IEnumerable. So join is possible between to IEnumerable objects.
However, List contains string value while IEnumerable object returned from SelectMany has integer value.
So created inner join query with string and integer value after converting integer to string. Refer screencast that might be required output
Screen cast showing working code
This Linq snippet may be helpful:
var allinone = (from l in MyList
join d in SomeDictionary.SelectMany(s => s.Value) on l equals d.Value
select d);

Try this:
var res = from l in MyList
from q in SomeDictionary
from w in q.Value
where w.Value == l
select w;
I get this:

C# LINQ converting a query to dictionary

A C# converting a query to dictionary:
public class myClass
{
public int my_id;
public Dictionary<string, Dictionary<string, string[]>> myDict;
}
Dictionary<string, myClass> dataDict;
Dictionary<int, Dictionary<string, myClass>> query = (from happen in dataDict
group happen by happen.Value.my_id into g
select g).ToDictionary( ?? );
I do not know what I should put in ( ?? ).
Any help would be appreciated.

Try this:
var query = (from happen in dataDict
group happen by happen.Value.my_id into g select g)
.ToDictionary(g => g.Key, g => g.ToDictionary(x => x.Key, x => x.Value));

Combining Dictionary<A,B> + Dictionary<B,C> to create Dictionary<A,C>

Any cool quick ways to take two dictionaries to create a third that maps the key of the first to the value of the second in an inner-join style?
Dictionary<A,B> dic1 = new Dictionary<A,B> {{a1,b1},{a2,b2},{a3,b3}};
Dictionary<B,C> dic2 = new Dictionary<B,C> {{b1,c1},{b2,c2},{b4,c4}};
Dictionary<A,C> dic3 = SomeFunction(dic1,dic2);
// dic3 = {{a1,c1},{a2,c2}}

You could do something like this to join on the inner value
Dictionary<int, string> first = new Dictionary<int, string> { {1, "hello"}, {2, "world"}};
Dictionary<string, bool> second =
new Dictionary<string, bool> { { "hello", true }, {"world", false}};
var result = (from f in first
join s in second on f.Value equals s.Key
select new { f.Key, s.Value }).ToDictionary(x => x.Key, y => y.Value);
If you dump out result you'll see it is a Dictionary with the value {1: true, 2: false}

try this -
Dictionary<string, string> a, b, c;
//code to initialize the 3 dictionaries. a,b are original dictionaries and c is the new dictionary
c = ( from ak in a.Keys
where b.ContainsKey( ak )
select new KeyValuePair<string, string>( ak, b[ ak ] ) ).ToDictionary( d => d.Key, d=> d.Value );

Maybe something with ToDictionary
dic1.Where(d1=>dic2.ContainsKey(d1.Value)).ToDictionary(d1=>d1.Key,d1=>dic2[d1.Value]);

Dictionary<int, string> dic1 = new Dictionary<int,string>();
Dictionary<string, decimal> dic2 = new Dictionary<string,decimal>();
dic1.Add(1, "one");
dic1.Add(2, "two");
dic1.Add(3, "three");
dic1.Add(4, "four");
dic1.Add(5, "five");
dic2.Add("one",1.0m);
dic2.Add("two", 2.0m);
dic2.Add("three", 3.0m);
dic2.Add("four", 4.0m);
dic2.Add("five", 5.0m);
Dictionary<int, decimal> result = (from d1 in dic1
from d2 in dic2
where d1.Value == d2.Key
select new { d1.Key, d2.Value }).ToDictionary(p=>p.Key, p=>p.Value);

public Dictionary<A,C> SomeFunction(dic1, dic2)
{
var dic3 = new Dictionary<A,C>();
foreach (var item in dic1)
{
var item2 = dic2.Where(m=>m.Key == item.Value).FirstOrDefault();
if (item2 != null)
{
dic3.Add(item.Key, item2.Value);
}
}
return dic3
}
I believe this will work for what you want

public IDictionary<A, C> SomeFunction<A, B, C>(IDictionary<A, B> dic1, IDictionary<B, C> dic2)
{
var dic3 = new Dictionary<A, C>();
foreach (var item in dic1)
{
var a = item.Key;
var b = item.Value;
if (dic2.ContainsKey(b))
{
var c = dic2[b];
dic3.Add(a, c);
}
}
return dic3;
}
Handles the case of dic2 not containing keys corresponding to dic1s value without fake null values being stored, and IMO is pretty clear. I do like some LINQ, but I thought I'd give a procedural answer for once...

The simplest solution:
var dict3 = dict1.ToDictionary(p => p.Key, p => dict2[p.Value]);

Linq expression. Help mimize code

Please, help minimize the following code:
There is a class with dictionary property:
class Foo
{
public int Field { get; set; }
public Dictionary<int, bool> dic { get; set; }
}
And a list of Foo instances. I want to get united dictionary from all class instances like that:
...
var items = new List<Foo>
{
new Foo {Field = 1, Dic = new Dictionary<int, bool> {{1, true}, {2, false}}},
new Foo {Field = 2, Dic = new Dictionary<int, bool> {{3, true}, {2, false}}}
};
var result = new Dictionary<int, bool>();
foreach (var dics in items.Select(x => x.Dic))
foreach (var pair in dics)
if (!result.ContainsKey(pair.Key))
result.Add(pair.Key, pair.Value);
// testing output
foreach (var pair in result)
Console.WriteLine("{0}, {1}", pair.Key, pair.Value);
Is it possible to do this with pure LINQ approach?
Thank you in advance!

You can use SelectMany to grab and flatten the inner dictionary elements:
var result = items.SelectMany(f => f.Dic)
.GroupBy(pair => pair.Key)
.ToDictionary(g => g.Key, g => g.First().Value);
edit: If you're feeling brave, this can be improved even further by picking up the DistinctBy method from Jon Skeet's morelinq project. Essentially, the GroupBy step is actually overkill, since all we really want is the first value for each key. If we select only the pairs with distinct keys, we can avoid the grouping and subsequent First call, like so:
var result = items.SelectMany(f => f.Dic)
.DistinctBy(pair => pair.Key)
.ToDictionary(pair => pair.Key, pair => pair.Value);

var result =
(from item in items
from pair in item.Dic
group pair by pair.Key
).ToDictionary(g => g.Key, g => g.First().Value);

I don't know if Distinct is better but it is shorter to write.
var result = items.SelectMany(d => d.Dic)
.Distinct()
.ToDictionary(p => p.Key, p => p.Value);
But I actually kind of like using foreach for this.
var result = new Dictionary<int, bool>();
foreach (var dic in items.SelectMany(d => d.Dic))
result[dic.Key] = dic.Value;