I'm working with a third part service of my client that is providing me a list of products and services, which is a little bit of a mess.
The list will return all of the services for the product but the product repeats itself, for example:
The product A has the service A and the product A also has the service B so, when i receive the list i will get two products A with services A and B
What i need to do is to group all of the products to get only one with all of it's services and i have done so but i'm worried about performance because i think my solution isn't the 'best' one:
var productsNormalized = products.Data.AsEnumerable().Select(x => new ProdutoSSO
{
CodigoServico = int.Parse(string.IsNullOrEmpty(x["CodigoServico"].ToString()) ? "0" : x["CodigoServico"].ToString()),
CodigoPeca = int.Parse(string.IsNullOrEmpty(x["CodigoPeca"].ToString()) ? "0" : x["CodigoPeca"].ToString()),
CodigoFamilia = int.Parse(string.IsNullOrEmpty(x["CodigoFamilia"].ToString()) ? "0" : x["CodigoFamilia"].ToString()),
Familia = x["Familia"].ToString(),
Servico = x["Servico"].ToString(),
Peca = x["Peca"].ToString(),
Hash = x["Hash"].ToString(),
Valor = decimal.Parse(string.IsNullOrEmpty(x["Valor"].ToString()) ? "0" : x["Valor"].ToString())
})
.GroupBy(x => new { x.CodigoPeca, x.CodigoFamilia, x.Familia, x.Peca })
.Select(x => new ProdutoGroup
{
Produto = new Produto
{
CodigoPeca = x.Key.CodigoPeca,
CodigoFamilia = x.Key.CodigoFamilia,
Familia = x.Key.Familia,
Peca = x.Key.Peca
},
Servicos = x.Select(y => new ProdutoServico
{
CodigoServico = y.CodigoServico,
Hash = y.Hash,
Servico = y.Servico,
Valor = y.Valor
}).ToList()
});
Is there a better way to achieve this or this is as good as it gets?
Using Aggregate you could do something like this (assuming you are starting with a list of ProdutoSSO, which might not be entirely necessary):
var productsNormalized = productoSSOs
.Aggregate(new Dictionary<Produto,List<ProdutoServico>>(ProductoComparer),
(p,c) => {
var product = new Produto
{
CodigoPeca = c.CodigoPeca,
CodigoFamilia = c.CodigoFamilia,
Familia = c.Familia,
Peca = c.Peca
};
var service = new ProdutoServico
{
CodigoServico = c.CodigoServico,
Hash = c.Hash,
Servico = c.Servico,
Valor = c.Valor
};
if (!p.ContainsKey(product))
{
p[product] = new List<ProductoServico>() { service };
}
else
{
p[product].Add(service);
}
return p;
});
Where ProductoComparer is an IEqualityComparer<Producto> (or alternatively you could implement Equals and GetHashCode in Producto, or you could just generate a key some other way - concatenating fields together, for example).
This is obviously untested since I don't have the original classes or data.
This would give you a Dictionary<Producto, List<ProductoServico>> which might be all you need, or you can easily transform it into an IEnumerable<ProdutoGroup> if you want.
Related
Here is class UserArrived:
public class UserArrived{
public string id{get;set;}
}
Here is class OldUser:
public class OldUser{
public string id{get;set;}
public DateTime lastArrived{get;set;}
}
And here is class User:
public class User{
public string id{get;set;}
public Boolean newUser{get;set;}
}
Finally, here is two List:
List<UserArrived> UserArrivedList=new List<UserArrived>();
List<OldUser> OldUserList=new List<OldUser>();
All the id in each class is unique.
Now I need to combine UserArrived and OldUser to a brand new List<User>.
As we know, the user arrives the shop may is a new user or an old user. If the user id in UserArrived also contains in OldUser, the property newUser in the new List is false for true.
In my opinion, I will combine two List into one first and then use the distinct method to remove the duplicates.
However, it seems the distinct can not run with a condition.
Although I can use several foreach to solve this while I feel it is so troublesome. I want to use something easy just like lambda or linq. How can I achieve this?
=============================
Here is an example of the input:
List<UserArrived> UserArrivedList=new List<UserArrived>(){new UserArrived(){id="A"},new UserArrived(){id="B"},new UserArrived(){id="C"}};
List<OldUser> OldUserList=new List<OldUser>(){new OldUser(){id="B",lastArrived=DateTime.Now}};
the output is:
A,true
B,false
C,true
If I understand your requirement you're saying that if an id is in both lists then the user is an old user, otherwise it is a new user.
So here's the simplest way that I could come up with to do it:
IEnumerable<User> users =
Enumerable
.Concat(
UserArrivedList.Select(i => i.id),
OldUserList.Select(i => i.id))
.ToLookup(x => x)
.Select(x => new User() { id = x.Key, newUser = x.Count() == 1 });
Let's test with some input:
var UserArrivedList = new List<UserArrived>()
{
new UserArrived() { id = "A" },
new UserArrived() { id = "B" },
};
var OldUserList = new List<OldUser>()
{
new OldUser() { id = "B" },
new OldUser() { id = "C" },
};
Here are my results:
B is the only user who appears in both lists so should be False.
So, there's a bit of confusion about the requirements here.
The OP has added a concrete example of the input data and the expected output.
var UserArrivedList = new List<UserArrived>()
{
new UserArrived() { id = "A" },
new UserArrived() { id = "B" },
new UserArrived() { id = "C" }
};
var OldUserList = new List<OldUser>()
{
new OldUser() { id = "B", lastArrived = DateTime.Now }
};
With this input the OP is expecting True, False, True for A, B, C respectively.
Here is the code of the four current answers:
var results = new []
{
new
{
answered = "Enigmativity",
users = Enumerable
.Concat(
UserArrivedList.Select(i => i.id),
OldUserList.Select(i => i.id))
.ToLookup(x => x)
.Select(x => new User() { id = x.Key, newUser = x.Count() == 1 })
},
new
{
answered = "JQSOFT",
users = UserArrivedList.Select(x => x.id)
.Concat(OldUserList.Select(y => y.id))
.Distinct()
.Select(x => new User
{
id = x,
newUser = OldUserList.Count(o => o.id == x) == 0,
})
},
new
{
answered = "Anu Viswan",
users =
UserArrivedList
.Join(OldUserList, ual => ual.id, oul => oul.id, (ual, oul) => new User { id = oul.id, newUser = false })
.Concat(UserArrivedList.Select(x => x.id).Except(OldUserList.Select(x => x.id))
.Concat(OldUserList.Select(x => x.id).Except(UserArrivedList.Select(x => x.id)))
.Select(x=> new User{ id = x, newUser = true}))
},
new
{
answered = "Barns",
users =
UserArrivedList.Select(i => i.id)
.Union(OldUserList.Select(i => i.id))
.Select(j => new User
{
id = j,
newUser =
!(UserArrivedList.Select(i => i.id).Contains(j)
&& OldUserList.Select(i => i.id).Contains(j))})
}
};
That gives the output of:
So, currently all of the answers presented match the OP's example.
I'd be interested in the OP commenting on this as the input data:
var UserArrivedList = new List<UserArrived>()
{
new UserArrived() { id = "A" },
new UserArrived() { id = "B" },
};
var OldUserList = new List<OldUser>()
{
new OldUser() { id = "B" },
new OldUser() { id = "C" },
};
When I run this I get this output:
Here three users match and one does not.
This all boils down to what the description means:
As we know, the user arrives the shop may is a new user or an old user. If the user id in UserArrived also contains in OldUser, the property newUser in the new List is false for true.
The thing about LINQ--it isn't always easy. In fact it can get quit cluttered. In the question statement I read,
I want to use something easy just like lambda or linq.
Well, that is relative. But, I think that when using LINQ, one should try to keep it simple. Even break the statement down into multiple statements if necessary. For that reason I propose this solution (demonstrated in a console app):
static void Main(string[] args)
{
Console.WriteLine();
Console.WriteLine("--------------------Test This Code -----------------------");
var combined = TestUserCombined();
//The following is just to demonstrate the list is populated properly
combined.OrderBy(s => s.id.PadLeft(4, '0')).ToList().ForEach(k => Console.WriteLine($"X id: {k.id} | isNew:{k.newUser}"));
}
private static IEnumerable<User> TestUserCombined()
{
List<UserArrived> userArrivedList=new List<UserArrived>();
List<OldUser> oldUserList=new List<OldUser>();
//populate the lists...
for(int i = 0; i < 20; i+=2)
{
var userArrived = new UserArrived();
userArrived.id = i.ToString();
userArrivedList.Add(userArrived);
}
for(int i = 0; i < 20; i+=3)
{
var oldUser = new OldUser();
oldUser.id = i.ToString();
oldUserList.Add(oldUser);
}
//Now for the solution...
var selectedUserArrived = userArrivedList.Select(i => i.id);
var selectedOldUser = oldUserList.Select(i => i.id);
var users = selectedUserArrived
.Union(selectedOldUser)
.Select(j => new User{id=j,newUser=!(selectedUserArrived.Contains(j) && selectedOldUser.Contains(j))});
return users;
}
Certainly, this all could have been done in one statement, but I believe this makes it more readable and understandable.
EDIT:
There has been some discussion amongst the coders posting solutions as to exactly what conditions must be met in order for the value "newUser" to be set to "true". It was my understanding from the initial posted question that the "id" must be present in both lists "UserArrivedList" AND "OldUserList", but I tend to agree with #JQSOFT that it makes more sense that the only condition that must be met should be that the "id" need only be present in "OldUserList". If that is indeed the case than the Select() expression above should be .Select(j => new User{id=j,newUser=!selectedOldUser.Contains(j)});
I hope I understood your query. One way to achieve this using Linq would be
var users = UserArrivedList.Join(OldUserList,ual=>ual.id,oul=>oul.id,(ual,oul)=>new User{id=oul.id,newUser=false})
.Concat(UserArrivedList.Select(x=>x.id).Except(OldUserList.Select(x=>x.id))
.Concat(OldUserList.Select(x=>x.id).Except(UserArrivedList.Select(x=>x.id)))
.Select(x=> new User{id=x,newUser=true}));
Now you need to create a distinct list of User type from two lists of different types; UserArrived and OldUser objects. A user is identified by a unique id of string type.
Accordingly, I'd suggest this:
var users = UserArrivedList.Select(x => x.id)
.Concat(OldUserList.Select(y => y.id))
.Distinct()
.Select(x => new User
{
id = x,
newUser = OldUserList.Count(o => o.id == x) == 0,
}).ToList();
Which gets the unique ids from both UserArrivedList and OldUserList and creates new User object for each. The OldUserList.Count(o => o.id == x) == 0, assigns false to the newUser property if the user id exists in the OldUserList otherwise true.
I have seen multiple questions that are similar to this one but I think my case is slightly different. I'm using EF6 to query the database and I'm using data projection for better queries.
Given that performance is very important on this project I have to make sure to just read the actual fields that I will use so I have very similar queries that are different for just a few fields as I have done this I have noticed repetition of the code so I'm been thinking on how to reuse code this is currently what I Have:
public static IEnumerable<FundWithReturns> GetSimpleFunds(this DbSet<Fund> funds, IEnumerable<int> fundsId)
{
IQueryable<Fund> query = GetFundsQuery(funds, fundsId);
var results = query
.Select(f => new FundWithReturns
{
Category = f.Category,
ExpenseRatio = f.ExpenseRatio,
FundId = f.FundId,
Name = f.Name,
LatestPrice = f.LatestPrice,
DailyReturns = f.FundDailyReturns
.Where(dr => dr.AdjustedValue != null)
.OrderByDescending(dr => dr.CloseDate)
.Select(dr => new DailyReturnPrice
{
CloseDate = dr.CloseDate,
Value = dr.AdjustedValue.Value,
}),
Returns = f.Returns.Select(r => new ReturnValues
{
Daily = r.AdjDaily,
FiveYear = r.AdjFiveYear,
MTD = r.AdjMTD,
OneYear = r.AdjOneYear,
QTD = r.AdjQTD,
SixMonth = r.AdjSixMonth,
ThreeYear = r.AdjThreeYear,
YTD = r.AdjYTD
}).FirstOrDefault()
})
.ToList();
foreach (var result in results)
{
result.DailyReturns = result.DailyReturns.ConvertClosingPricesToDailyReturns();
}
return results;
}
public static IEnumerable<FundListVm> GetFundListVm(this DbSet<Fund> funds, string type)
{
return funds
.Where(f => f.StatusCode == MetisDataObjectStatusCodes.ACTIVE
&& f.Type == type)
.Select(f => new FundListVm
{
Category = f.Category,
Name = f.Name,
Symbol = f.Symbol,
Yield = f.Yield,
ExpenseRatio = f.ExpenseRatio,
LatestDate = f.LatestDate,
Returns = f.Returns.Select(r => new ReturnValues
{
Daily = r.AdjDaily,
FiveYear = r.AdjFiveYear,
MTD = r.AdjMTD,
OneYear = r.AdjOneYear,
QTD = r.AdjQTD,
SixMonth = r.AdjSixMonth,
ThreeYear = r.AdjThreeYear,
YTD = r.AdjYTD
}).FirstOrDefault()
}).OrderBy(f=>f.Symbol).Take(30).ToList();
}
I'm trying to reuse the part where I map the f.Returns so I tried created a Func<> like the following:
private static Func<Return, ReturnValues> MapToReturnValues = r => new ReturnValues
{
Daily = r.AdjDaily,
FiveYear = r.AdjFiveYear,
MTD = r.AdjMTD,
OneYear = r.AdjOneYear,
QTD = r.AdjQTD,
SixMonth = r.AdjSixMonth,
ThreeYear = r.AdjThreeYear,
YTD = r.AdjYTD
};
and then use like this:
public static IEnumerable<FundListVm> GetFundListVm(this DbSet<Fund> funds, string type)
{
return funds
.Where(f => f.StatusCode == MetisDataObjectStatusCodes.ACTIVE
&& f.Type == type)
.Select(f => new FundListVm
{
Category = f.Category,
Name = f.Name,
Symbol = f.Symbol,
Yield = f.Yield,
ExpenseRatio = f.ExpenseRatio,
LatestDate = f.LatestDate,
Returns = f.Returns.Select(MapToReturnValues).FirstOrDefault()
}).OrderBy(f=>f.Symbol).Take(30).ToList();
}
The compiler is ok with it but at runtime, it crashes and says: Internal .NET Framework Data Provider error 1025
I tried to convert the Func into Expression like I read on some questions and then using compile() but It didn't work using AsEnumerable is also not an option because It will query all the fields first which is what I want to avoid.
Am I trying something not possible?
Thank you for your time.
It definitely needs to be Expression<Func<...>>. But instead of using Compile() method (not supported), you can resolve the compile time error using the AsQueryable() method which is perfectly supported (in EF6, the trick doesn't work in current EF Core).
Given the modified definition
private static Expression<Func<Return, ReturnValues>> MapToReturnValues =
r => new ReturnValues { ... };
the sample usage would be
Returns = f.Returns.AsQueryable().Select(MapToReturnValues).FirstOrDefault()
I am selecting data from a data store
I am able to fetch first array [0] {IHSWCFService.ServiceReference1.Observation} using below query
var newData = data.Select(a => new IHSData
{
PriceSymbol = Convert.ToString(a.PriceId),
PeriodData = Convert.ToDateTime(a.ObservationVector.Select(x => x.Period).FirstOrDefault()),
StatusID = Convert.ToInt32(a.ObservationVector.Select(x => x.StatusId).ToList()),
Price = Convert.ToDouble(a.ObservationVector.Select(x => x.price).FirstOrDefault()),
});
But I want to select next array also. as showing in below screen screenshot
[0]{IHSWCFService.ServiceReference1.Observation}
[1]{IHSWCFService.ServiceReference1.Observation}
[2]{IHSWCFService.ServiceReference1.Observation}
Could you please help me. Thanks
You might want all your properties in IHSData to be lists:
var newData = data.Select(a => new IHSData
{
PriceSymbol = Convert.ToString(a.PriceId),
PeriodData = a.ObservationVector.Select(x => Convert.ToDateTime(x.Period)).ToList(),
StatusID = a.ObservationVector.Select(x => Convert.ToInt32(x.StatusId)).ToList(),
Price = a.ObservationVector.Select(x => Convert.ToDouble(x.price)).ToList(),
});
Which is not such a good idea, because you have to index them separately. So another option would be to use SelectMany:
var newData = data
.SelectMany(a => a.ObservationVector.Select(v =>
new IHSData
{
PriceSymbol = Convert.ToString(a.PriceId), // parent PriceId
PeriodData = Convert.ToDateTime(v.Period),
StatusID = Convert.ToInt32(v.StatusId),
Price = Convert.ToDouble(v.price),
}))
.ToList();
The latter approach will create a separate IHSData instance for each ObservationVector, and some of them will share the same PriceId of the parent class.
Or, the third approach would be to have a new class, which would be the "parsed version of the ObservationVector", i.e. contain properties for parsed values, something like:
var newData = data.Select(a => new IHSData
{
PriceSymbol = Convert.ToString(a.PriceId),
Data = a.ObservationVector.Select(x => ConvertObservationVector(x)).ToList()
});
where ConvertObservationVector is a method which converts from an ObservationVector to your parsed class.
I have a ControlMeasure table that holds information on each control measure and a ControlMeasurepeopleExposed Table that holds a record for each person exposed in the control measure this could be 1 record or many records.
I Have a controller that populates a List view
For each item in the list, Control Measure, I would like to create a string that shows all the People at risk
e.g.
PeopleString = "Employees, Public, Others";
Ive added a foreach in the controller to show what I'm trying to do however I'm aware that this wont work.
The controller is this:
public ActionResult ControlMeasureList(int raId)
{
//Populate the list
var hazards = new List<Hazard>(db.Hazards);
var controlMeasures = new List<ControlMeasure>(db.ControlMeasures).Where(x => x.RiskAssessmentId == raId);
var cmcombined = (
from g in hazards
join f in controlMeasures
on new { g.HazardId } equals new { f.HazardId }
select new CMCombined
{
Activity = f.Activity,
ControlMeasureId = f.ControlMeasureId,
ExistingMeasure = f.ExistingMeasure,
HazardName = g.Name,
LikelihoodId = f.LikelihoodId,
Rating = f.Rating,
RiskAssessmentId = f.RiskAssessmentId,
SeverityId = f.SeverityId,
}).OrderBy(x => x.Activity).ToList();
var cmPeopleExp = new List<ControlMeasurePeopleExposed>(db.ControlMeasurePeopleExposeds).Where(x => x.RiskAssessmentId == raId);
var peopleExp = from c in cmPeopleExp
join d in db.PeopleExposeds
on c.PeopleExposedId equals d.PeopleExposedId
orderby d.Name
select new RAPeopleExp
{
RAPeopleExpId = c.PeopleExposedId,
PeopleExpId = c.PeopleExposedId,
PeopleExpName = d.Name,
RiskAssessmentId = c.RiskAssessmentId,
ControlMeasureId = c.ControlMeasureId
};
var model = cmcombined.Select(t => new FullControlMeasureListViewModel
{
ControlMeasureId = t.ControlMeasureId,
HazardName = t.HazardName,
LikelihoodId = t.LikelihoodId,
Rating = t.Rating,
SeverityId = t.SeverityId,
Activity = t.Activity,
ExCM = t.ExistingMeasure,
//This section here is where I'm struggling
var PeopleString = new StringBuilder();
foreach (var p in peopleExp)
{
PeopleString.AppendLine(p.PeopleName);
{
PeopleExposed = PeopleString,
});
return PartialView("_ControlMeasureList", model);
}
I know I cant directly put this code in the controller but it does represent what I want to do.
You can't foreach within an object initializer (which is what you're trying to do when instantiating FullControlMeasureListViewModel). You can, however, use a combination of string.Join and peopleExp.Select:
var model = cmcombined.Select(t => new FullControlMeasureListViewModel
{
//other props
PeopleExposed = string.Join(",", peopleExp
.Where(p => p.ControlMeasureId == t.ControlMeasureId)
.Select(p => p.PeopleExpName));
//other props
});
The code below is what I currently have and works fine. I feel that I could do more of the work I am doing in Linq instead of C# code.
Is there is anyone out there who can accomplish the same result with more Linq code and less C# code.
public List<Model.Question> GetSurveyQuestions(string type, int typeID)
{
using (eMTADataContext db = DataContextFactory.CreateContext())
{
List<Model.Question> questions = new List<Model.Question>();
List<Linq.Survey_Question> survey_questions;
List<Linq.Survey> surveys = db.Surveys
.Where(s => s.Type.Equals(type) && s.Type_ID.Equals(typeID))
.ToList();
if (surveys.Count > 0)
{
survey_questions = db.Survey_Questions
.Where(sq => sq.Survey_ID == surveys[0].ID).ToList();
foreach (Linq.Survey_Question sq in survey_questions)
{
Model.Question q = Mapper.ToBusinessObject(sq.Question);
q.Status = sq.Status;
questions.Add(q);
}
}
else
{
questions = null;
}
return questions;
}
}
Here is my Mapper function from my Entity to Biz Object
internal static Model.Question ToBusinessObject(Linq.Question q)
{
return new Model.Question
{
ID = q.ID,
Name = q.Name,
Text = q.Text,
Choices = ToBusinessObject(q.Question_Choices.ToList())
};
}
I want my mapper funciton to map the Question Status like so.
internal static Model.Question ToBusinessObject(Linq.Question q)
{
return new Model.Question
{
ID = q.ID,
Name = q.Name,
Text = q.Text,
Choices = ToBusinessObject(q.Question_Choices.ToList()),
Status = q.Survey_Questions[?].Status
};
}
? the issue is this function does not know which survey to pull the status from.
Instead of creating the biz object then setting the Status property in a foreach loop like so
foreach (Linq.Survey_Question sq in survey_questions)
{
Model.Question q = Mapper.ToBusinessObject(sq.Question);
q.Status = sq.Status;
questions.Add(q);
}
I would like to somehow filter the EntitySet<Survey_Question> in the q object above in the calling method, such that there would only be one item in the q.Survey_Questions[?] collection.
below is my database schema and business object schema
What I needed to do was setup a join.
public List<Model.Question> GetSurveyQuestions(string type, int typeID)
{
using (eMTADataContext db = DataContextFactory.CreateContext())
{
return db.Survey_Questions
.Where(s => s.Survey.Type.Equals(type) && s.Survey.Type_ID.Equals(typeID))
.Join(db.Questions,
sq => sq.Question_ID,
q => q.ID,
(sq, q) => Mapper.ToBusinessObject(q, sq.Status)).ToList();
}
}
And then overload my Mapper Function
internal static Model.Question ToBusinessObject(Linq.Question q, string status)
{
return new Model.Question
{
ID = q.ID,
Name = q.Name,
Text = q.Text,
Status = status,
Choices = ToBusinessObject(q.Question_Choices.ToList()),
};
}
from question in db.Survey_Questions
let surveys = (from s in db.Surveys
where string.Equals(s.Type, type, StringComparison.InvariantCultureIgnoreCase) &&
s.Type_ID == typeID)
where surveys.Any() &&
surveys.Contains(s => s.ID == question.ID)
select new Mapper.Question
{
ID = question.Id,
Name = question.Name,
Text = question.Text,
Choices = ToBusinessObject(question.Question_Choices.ToList()),
Status = question.Status
}
Does that get you on the right track?
Why are you duplicating all your classes? You could just extend the LINQ to SQL classes with your business logic - they are partial classes. This is somewhat against the purpose of an OR mapper - persisting business entities.