If I had a collection like :
var list = new List<string>()
{
"one",
"one",
"two",
"two",
"three"
};
is it possible to get a result like below using linq?
"one-1", "one-2", "two-1", "two-2", "three"
I am trying to get duplicate values and append consecutive numbers to them to make them unique
|EDIT
I did this in LinqPad, seems right...
Dictionary<string,string> names = new Dictionary<string,string>(){
{"val1","text1"},
{"val2","text1"},
{"val3","text2"},
{"val4","text3"},
{"val5","text3"}
};
var filteredNames = names.GroupBy (x => x.Value).ToDictionary(x => x.Key, x => x.Select((i, index) => i.Value + index.ToString()));
advice welcome!
Starting from the list you should do as follows:
var filteredNames = list.GroupBy (x => x).SelectMany((i, index) => i.Value + "-" + index.ToString());
Starting from the dictionary your solution is right, but if you want as a result a list you should do as follows:
var filteredNames = names.GroupBy (x => x.Value).SelectMany((i, index) => i.Value + "-" + index.ToString());
Related
I've got a CQLinq query which returns a list of methods and a list of members for each of them. Exporting the query result will only show the number of elements. I thought about using a Linq Aggregate( (a,b) => a + ',' + b). Is there a better solution?
let type = Application.Types.WithFullName("WPF.ViewModels.CouponViewModel").Single()
let dicoFields = type.Fields
.ToDictionary(f => f, f => f.MethodsUsingMe.Where(m => m.ParentType == f.ParentType))
let dicoMethods = type.Methods
.ToDictionary(m => m, m => m.MembersUsed.Where(f => f.ParentType == m.ParentType))
// The partition algorithm on both dicos here
//from pair in dicoFields
//orderby pair.Value.Count() descending
//select new { pair.Key, pair.Value }
from pair in dicoMethods
orderby pair.Value.Count() descending
select new { pair.Key, pair.Value}
Indeed you can rewrite your query this way:
let type = Application.Types.WithFullName("WPF.ViewModels.CouponViewModel").Single()
let dicoMembers = type.ChildMembers
.ToDictionary(x => x, x =>
x.IsField ? x.AsField.MethodsUsingMe.Where(m => m.ParentType == x.ParentType):
x.AsMethod.MembersUsed.Where(f => f.ParentType == x.ParentType))
from pair in dicoMembers
orderby pair.Value.Count() descending
select new {
pair.Key,
str = pair.Value.Any() ?
pair.Value.Select(x => x.Name).Aggregate( (a,b) => a + " ; " + b) :
"empty"
}
Both methods and fields are taken account
Methods using fields and members used by methods are aggregated in a string
Then you can export the result:
I have the following data structure:
Dictionary<string, Dictionary<string, List<int>>> data =
new Dictionary<string, Dictionary<string, List<int>>>();
I want to filter some of the elements in that dictionary based on value in first element of the list of the inner dictionary.
for example:
{legion1
{soldier1, [10,1000]},
{soldier2, [50,1000]}
}
Now let's say I want to do foreach loop in which to work only elements where
the value of the first element of the list is less than 20
expected result in the foreach loop is:
{legion1{soldier1, [10,1000]}}
What I've tried:
I do foreach loop and then I want to use something similar:
data.where(x => x.value.where(o => o[0] < 20 ))
I always get error that that way is incorrect.
Please tell how can I solve the issue and why my way is failing.
You can filter and iterate over the result set like so:
var resultSet =
data.ToDictionary(e => e.Key,
e => e.Value.Where(x => x.Value[0] < 20)
.ToDictionary(k => k.Key, v => v.Value)
);
foreach(var item in resultSet){
var key = item.Key; // string
var values = item.Value; // Dictionary<string, List<int>>
...
...
}
The problem is that you are applying operator [] incorrectly. Moreover, since you want to use both Legion and Soldier, you should construct a tuple combining the two of them:
foreach (var t in data.SelectMany(lg => lg.Value.Select(s => new {
Legion = lg
, Soldier = s
})).Where(ls => ls.Soldier.Value[0] < 20)) {
Console.WriteLine("Legion={0} Soldier = {1}", t.Legion.Key, t.Soldier.Key);
}
Hi I have a List so:
A 1
A 2
A 3
A 4
B 1
B 2
C 1
I want to select the letter that contains AT LEAST these 3 numbers: 1,2,3
So in this case would be selected the letter A.
Can you help me to write this as LINQ expression?
Thanks a lot!
First, make a collection of the numbers you require.
var required = new[] { 1, 2, 3 };
Then, group your pairings by letter.
var groupedPairings = pairings.GroupBy(p => Letter, p => Number);
Then, discard those pairings that don't have your three required items. (The logic here is "take the collection of required items, remove anything in the group, and make sure there is nothing left".)
var groupsWithRequired = groupedPairings
.Where(g => !required.Except(g).Any());
Now, if you just want the letters, you can simply do
var lettersWithRequired = groupsWithRequired.Select(g => g.Key);
or if you want a dictionary mapping from the letter to its collection of numbers, you can do
var dictionary = groupsWithRequired.ToDictionary(g => g.Key, g => g.ToArray());
var numbersForA = dictionary["A"]; // = {1, 2, 3, 4}
You could try this, although I don't feel it's the best answer:
var items = new List<Item>{
new Item{Name="A", Value=1},
new Item{Name="A", Value=2},
new Item{Name="A", Value=3},
new Item{Name="A", Value=3},
new Item{Name="A", Value=4},
new Item{Name="B", Value=1},
new Item{Name="B", Value=2},
new Item{Name="C", Value=1},
};
var values = new List<int>{1,2,3};
var query = items.GroupBy (i => i.Name)
.Where (i => i.Select (x => x.Value)
.Intersect(values).Count() == values.Count)
.Select (i => i.Key);
Where
class Item{
public string Name{get;set;}
public int Value{get;set;}
}
I need to return all records (items) that has a part (X) so I can use that in a group or .GroupBy afterwards
Using this summary data:
ItemName PartName
1 A
1 B
2 A
3 C
So Item1 has two parts (A,B), etc...
I need a LINQ query that will
- find all items that have part A (i.e items 1 and 2)
- return all rows for all these items
1 A
1 B
2 A
Notice that the end result returned the row (1 B) because Item1 has PartA and so I need to get back all rows for Item1.
I was looking at something like:
let items = from data in summary where data.PartName == A select new { data.ItemName } // to get all the items I need
But then, now that I have that list I need to use it to get all the rows for all items listed, and I can't seem to figure it out ...
Actual Source Code (for reference):
NOTE:
Recipe = ITEM
Ingredient = PART
(I was just trying to make it simpler)
ViewFullRecipeGrouping = (
from data in ViewRecipeSummary
group data by data.RecipeName into recipeGroup
let fullIngredientGroups = recipeGroup.GroupBy(x => x.IngredientName)
select new ViewFullRecipe()
{
RecipeName = recipeGroup.Key,
RecipeIngredients = (
from ingredientGroup in fullIngredientGroups
select new GroupIngredient()
{
IngredientName = ingredientGroup.Key
}
).ToList(),
ViewGroupRecipes = (
from data in ViewRecipeSummary
// this is where I am looking to add the new logic to define something I can then use within the next select statement that has the right data based on the information I got earlier in this query.
let a = ViewRecipeSummary.GroupBy(x => x.RecipeName)
.Where(g => g.Any(x => x.IngredientName == recipeGroup.Key))
.Select(g => new ViewRecipe()
{
RecipeName = g.Key,
IngredientName = g.Select(x => x.IngredientName)
})
select new GroupRecipe()
{
// use the new stuff here
}).ToList(),
}).ToList();
Any help would be much appreciated.
Thanks,
I believe this does what you want:
var data = /* enumerable containing rows in your table */;
var part = "X";
var items = new HashSet<int>(data
.Where(x => x.PartName == part)
.Select(x => x.ItemName));
var query = data.Where(x => items.Contains(x.ItemName));
If I understand your comment at the end, I believe this also does what you want:
var query = data
.GroupBy(x => x.ItemName)
.Where(g => g.Any(x => x.PartName == part))
.Select(g => new
{
ItemName = g.Key,
PartNames = g.Select(x => x.PartName)
});
I want to convert this LINQ code
var x = from nm in names
select MyClass.SomeMethod(nm).TrimStart(',');
foreach (var vv in x)
{
// I want to group and count different types of vv here
}
to use shorter syntax, one where they do x => x in LINQ. I also want to group and count 'vv' (there could be number of similar vv's)
Well, the "dot notation" or "fluent notation" for the above is:
var x = names.Select(nm => MyClass.SomeMethod(nm).TrimStart(','));
For grouping:
var x = names.Select(nm => MyClass.SomeMethod(nm).TrimStart(','));
.GroupBy(vv => vv,
(key, group) => new { Key = key, Count = group.Count() });
Something like this?
MyClass.SomeMethod(names).TrimStart(',')
.GroupBy(x => x.vv)
.ToList()
.ForEach(x => Console.WriteLine(x.Key + ": " + x.Count()));