Develop Reference

Sorting List Array based on an index of array

I want to sort a List Array on the basis of an array item.
I have a List Array of Strings as below:
List<String>[] MyProjects = new List<String>[20];
Through a loop, I have added five strings
(Id, Name, StartDate, EndDate, Status)
to each of the 20 projects from another detailed List source.
for(int i = 0; i<20; i++){
MyProjects[i].Add(DetailedProjectList.Id.ToString());
MyProjects[i].Add(DetailedProjectList.Name);
MyProjects[i].Add(DetailedProjectList.StartDate);
MyProjects[i].Add(DetailedProjectList.EndDate);
MyProjects[i].Add(DetailedProjectList.Status)}
The Status values are
"Slow", "Normal", "Fast", "Suspended" and "" for unknown status.
Based on Status, I want to sort MyProject List Array.
What I have done is that I have created another List as below
List<string> sortProjectsBy = new List<string>(){"Slow", "Normal", "Fast", "", "Suspended"};
I tried as below to sort, however unsuccessful.
MyProjects = MyProjects.OrderBy(x => sortProjectsBy.IndexOf(4));
Can anyone hint in the right direction. Thanks.

I suggest you to create class Project and then add all the fields inside it you need. It's much nicer and scalable in the future. Then create a List or an Array of projects and use the OrderBy() function to sort based on the field you want.
List<Project> projects = new List<>();
// Fill the list...
projects.OrderBy(project => project.Status);
The field Status has to be a primitive type or needs to implement the interface IComparable in order for the sorting to work. I suggest you add an enum for Status with int values.

First consider maybe to use Enum for status and put it in a different file lite (utils or something) - better to work like that.
enum Status {"Slow"=1, "Normal", "Fast", "", "Suspend"}
Now about the filtering you want to achieve do it like this (you need to tell which attribute of x you are referring to. In this case is status)
MyProjects = MyProjects.OrderBy(x => x.status == enum.Suspend);
Read about enums :
https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/enum
Read about lambda expressions :
https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/statements-expressions-operators/lambda-expressions

First of all, storing project details as List is not adivisable. You need to create a Custom Class to represent them.
For example,
public class DetailedProjectList
{
public string Name {get;set;}
public eStatus Status {get;set;}
// rest of properties
}
Then You can use
var result = MyProjects.OrderBy(x=> sortProjectsBy.IndexOf(x.Status));
For example
List<string> sortProjectsBy = new List<string>(){"Slow", "Normal", "Fast", "", "Suspended"};
var MyProjects= new List<DetailedProjectList>{
new DetailedProjectList{Name="abc1", Status="Fast"},
new DetailedProjectList{Name="abc2", Status="Normal"},
new DetailedProjectList{Name="abc3", Status="Slow"},
};
var result = MyProjects.OrderBy(x=> sortProjectsBy.IndexOf(x.Status));
Output
abc3 Slow
abc2 Normal
abc1 Fast
A better approach thought would be to use Enum to represent Status.
public enum eStatus
{
Slow,
Normal,
Fast,
Unknown,
Suspended
}
Then your code can be simplified as
var MyProjects= new List<DetailedProjectList>{
new DetailedProjectList{Name="abc1", Status=eStatus.Fast},
new DetailedProjectList{Name="abc2", Status=eStatus.Normal},
new DetailedProjectList{Name="abc3", Status=eStatus.Slow},
};
var result = MyProjects.OrderBy(x=> x.Status);

Ok so you have a collection of 20 items. Based on them you need to create a list of strings(20 DetailedProjectList items).
What you can do to solve your problem is to SORT YOUR COLLECTION before you create your list of strings. In this way your list of strings will be sorted.
But your code is not optimal at all. So you should concider optimization on many levels.

Lets say you have ProjectDetail class as follow:
private class ProjectDetail
{
public int Id {get;set;}
public string Name {get;set;}
DateTime StartDate {get;set;} = DateTime.Now;
DateTime EndDate {get;set;} = DateTime.Now;
public string Status {get;set;}
public string toString => $"{Id} - {Name} - {StartDate} - {EndDate} - {Status}";
}
Notice that I have added a toString attribute to make things easier, and I also have added default values.
Then your program could be like:
static void Main(string[] args)
{
var projectDetails = MockProjectItems();
Console.WriteLine("Before sortig:");
foreach (var item in projectDetails)
{
Console.WriteLine(item.toString);
}
var myProjects = projectDetails.OrderBy(p => p.Status).Select(p => p.toString);
Console.WriteLine("\n\nAfter sorting:");
foreach (var item in myProjects)
{
Console.WriteLine(item);
}
}
where the helper method is
private static List<ProjectDetail> MockProjectItems()
{
var items = new List<ProjectDetail>(20);
for(int i = 0; i < 20 ; i += 4){
items.Add(new ProjectDetail{Id = i, Name = "RandomName "+i, Status = "Slow"});
items.Add(new ProjectDetail{Id = i+1, Name = "RandomName "+(i+1), Status = "Normal"});
items.Add(new ProjectDetail{Id = i+2, Name = "RandomName "+(i+2), Status = "Fast"});
items.Add(new ProjectDetail{Id = i+3, Name = "RandomName "+(i+3), Status = "Suspended"});
}
return items;
}
Then your program should print the following:

Match sections of a List, and Replace if both exist

I've got dates from separate countries within a single List<>. I'm trying to get two records that contain the same characters before the second comma, and replace BOTH of those items with a new one.
Example:
From This:
18/04/2014,Good Friday,England and Wales
18/04/2014,Good Friday,Scotland
Into this:
18/04/2014,Good Friday,"England, Wales and Scotland"
Please note there may be multiple scenarios within the list like the above example. I've managed to get everything before the second Comma with:
splitSubstring = line.Remove(line.LastIndexOf(','));
I've tried the below, but it's clearly flawed since it won't delete both the records even if it does find a match:
foreach (var line in orderedLines)
{
if (splitSubstring == line.Remove(line.LastIndexOf(',')))
{
//Replace if previous is match here
}
splitSubstring = line.Remove(line.LastIndexOf(','));
File.AppendAllText(correctFile, line);
}

I would suggest parsing it into a structure you can work with e.g.
public class HolidayInfo
{
public DateTime Date { get; set; }
public string Name { get; set; }
public string[] Countries { get; set; }
};
And then
string[] lines = new string[]
{
"18/04/2014,Good Friday,England and Wales",
"18/04/2014,Good Friday,Scotland"
};
// splits the lines into an array of strings
IEnumerable<string[]> parsed = lines.Select(l => l.Split(','));
// copy the parsed lines into a data structure you can write code against
IEnumerable<HolidayInfo> info = parsed
.Select(l => new HolidayInfo
{
Date = DateTime.Parse(l[0]),
Name = l[1],
Countries = l[2].Split(new[] {",", " and " }, StringSplitOptions.RemoveEmptyEntries)
});
...etc. And once you have it in a helpful data structure you can begin to develop the required logic. The above code is just an example, the approach is what you should focus on.

I ended up using LINQ to pull apart the List and .Add() them into another based on an if statement. LINQ made it nice and simple.
//Using LINQ to seperate the two locations from the list.
var seperateScotland = from s in toBeInsertedList
where s.HolidayLocation == scotlandName
select s;
var seperateEngland = from e in toBeInsertedList
where e.HolidayLocation == engAndWales
select e;
Thanks for pointing me to LINQ

How to combine two c# objects using Linq

I am trying to combine two LIKE objects together and remove duplicates.
Tried this
This didn't work
Here is my object [simple]
public class LabelItem
{
public string LabelName { get; set; }
public string LabelValue { get; set; }
}
my data call returns the same object type
public static List<LabelItem> ReturnControlLabelList(Enums.LanguageType languageType, string labelList = "")
I pass this to the method
string[] LABELLIST = new string[] { "foxLabel", "commonLabel" };
var helper = new LabelHelper(, LABELLIST);
this is where I get null
public LabelHelper(Enums.LanguageType languageType, string[] labelListName)
{
if (labelListName != null)
{
List<LabelItem> labels = new List<LabelItem>();
this.LabelList = new List<LabelItem>();
foreach (var name in labelListName)
{
labels = DBCommon.ReturnControlLabelList(languageType, name);
this.LabelList.Concat(labels).Distinct().ToList();
}
}
else
{
this.LabelList = null;
}
}
public List<LabelItem> LabelList { get; private set; }
The concat is not working. I keep getting count 0 for labels and I can see the returns come back with 275 and 125 in the for loop.
Thanks in advance for the help.
Still having an issue
I want to use the suggestion from below but am still struggling.
The string[] passed in will get two lists of labelitems that are not unique when joined together in the loop. I need the distinct of the multiple lists returned in this.LabelList.
I got it to work with this but...I'm sure it's crazy inefficient.
Thanks for the help.
this.LabelList = new List<LabelItem>();
foreach (var name in labelListName)
{
var ret = DBCommon.ReturnControlLabelList(languageType, name);
this.LabelList = this.LabelList.Concat(ret).Distinct().ToList();
}
var distinctList = this.LabelList.GroupBy(x => new { x.LabelName, x.LabelValue })
.Select(x => x.FirstOrDefault());
this.LabelList = new List<LabelItem>();
foreach (var item in distinctList)
{
this.LabelList.Add(item);
Debug.WriteLine(item.LabelName + ' ' + item.LabelValue);
}
}

this.LabelList.Concat(labels).Distinct().ToList(); without assigning it to something doesn't make much sense. LINQ query does not modify the source collection, it returns a new one, so you'd have to assign it back to this.LabelList if you want it to get updated:
this.LabelList = this.LabelList.Concat(labels).Distinct().ToList();
You should be aware, that it's highly inefficient solution, and you should go with something based on SelectMany:
this.LabelList
= labelListName.SelectMany(name => DBCommon.ReturnControlLabelList(languageType, name)
.Distinct()
.ToList();

Concat and most other linq methods return an IEnumerable which you then need to do something with. It will not change your existing list so you need to just assign it with:
this.LabelList = this.LabelList.Concat(labels).Distinct().ToList();

Extract data into datatable to draw multiple graphs on one chart

I am working on a project that aims to extract and treat data for statitics purpose.
Let's say I have many elements "E" and each element has a list of fields {F1, F2, F3, ...}.
My main table looks like the following:
I need to extract data by elementID into a data table with "Date" as Key.
[{"key": "date1",
"F1": "value",
"F2": "value"}
,{"key": "date2",
"F1": "value",
"F2": "value"}
,{"key": "date3",
"F1": "value",
"F2": "value"}
,{....}]
My current implementation is the following does the next:
1) Query from database by field and order by date in a Dictionary<DateTime, double>
2) Check and fill missing values in each Dictionary.
3) Loop through the list or Dictionary by key and fill a DataRow a row by row.
I don't think that this is the ultimate solution, I have been trying to optimize code. But I am not really sure in wich layer I should focus. Is there any possible way to get the required structure using a select from database ( no need to further loops ) ?

It's not that clear, however, i assume that you want to group by the date-part of the DateTime and select a dictionary where this date is the key and the value is a List<double>.
Then you don't need a DataTable at all. Instead of a double i would use custom classes with all properties. Assuming that mainTable is already a DataTable with the raw data:
public class ElementMeasurement
{
public Element Element { get; set; }
public double Value { get; set; }
public string Field { get; set; }
public DateTime Date { get; set; }
}
public class Element
{
public int ElementID { get; set; }
public string Name { get; set; }
}
Now you can use Enumerable.GroupBy which is part of System.Linq:
Dictionary<DateTime, List<ElementMeasurement>> dateMeasurements = mainTable.AsEnumerable()
.GroupBy(row => row.Field<DateTime>("Date").Date)
.ToDictionary(g =>
g.Key,
g => g.Select(row => new ElementMeasurement
{
Element = new Element { ElementId = row.Field<int>("ElementId") },
Field = row.Field<string>("Field"),
Value = row.Field<double>("Value"),
TimeOfMeasurement = row.Field<DateTime>("Date")
}).ToList()
);
Edit: "Well I should let you know that it is a huge table with thousands of miles of rows!"
I didnt know that the table was not already in memory. Then this might be too memory expensive. So maybe a loop on the DataReader which yields rows ordered by Date is more efficient. Then you could still use my classes above to keep it readable and maintainable but fill the Dictionary step-by-step.
For example (assuming SQL-Server):
var dateMeasurements = new Dictionary<DateTime, List<ElementMeasurement>>();
using(var con = new SqlConnection("ConnectionString"))
using (var cmd = new SqlCommand("SELECT e.* FROM Elements e ORDER BY Date,ElementId,Field,Value", con))
{
con.Open();
using (var rd = cmd.ExecuteReader())
while(rd.Read())
{
DateTime timeOfMeasurement = rd.GetDateTime(rd.GetOrdinal("Date"));
DateTime dateOfMeasurement = timeOfMeasurement.Date;
List<ElementMeasurement> measurements = null;
if (!dateMeasurements.TryGetValue(dateOfMeasurement, out measurements))
{
measurements = new List<ElementMeasurement>();
dateMeasurements.Add(dateOfMeasurement, measurements);
}
var measurement = new ElementMeasurement
{
Element = new Element { ElementId = rd.GetInt32(rd.GetOrdinal("ElementId")) },
Field = rd.GetString(rd.GetOrdinal("Field")),
Value = rd.GetDouble(rd.GetOrdinal("Value")),
TimeOfMeasurement = timeOfMeasurement
};
measurements.Add(measurement);
}
}

Cannot implicitly convert type '.List<AnonymousType#1>' to '.List<WebApplication2.Customer>'

In the following code that returns a list:
public List<Customer> GeAllCust()
{
var results = db.Customers
.Select(x => new { x.CustName, x.CustEmail, x.CustAddress, x.CustContactNo })
.ToList()
return results;
}
I get an error reporting that C# can't convert the list:
Error: Cannot implicitly convert type System.Collections.Generic.List<AnonymousType#1> to System.Collections.Generic.List<WebApplication2.Customer>
Why is that?
Here's a screenshot showing some additional information that Visual Studio provides in a tooltip for the error:
Is it right way to return some columns instead of whole table....?
public object GeAllCust()
{
var results = db.Customers.Select(x => new { x.CustName, x.CustEmail, x.CustAddress, x.CustContactNo }).ToList();
return results;
}

When you look the code:
x => new { ... }
This creates a new anonymous type. If you don't need to pull back only a particular set of columns, you can just do the following:
return db.Customers.ToList();
This assumes that Customers is an IEnumerable<Customer>, which should match up with what you are trying to return.
Edit
You have noted that you only want to return a certain subset of columns. If you want any sort of compiler help when coding this, you need to make a custom class to hold the values:
public class CustomerMinInfo
{
public string Name { get; set; }
public string Email { get; set; }
public string Address { get; set; }
public int? ContactNumber { get; set; }
}
Then change your function to the following:
public List<CustomerMinInfo> GetAllCust()
{
var results = db.Customers.Select(x => new CustomerMinInfo()
{
Name = x.CustName,
Email = x.Email,
Address = x.Address,
ContactNumber = x.CustContactNo
})
.ToList();
return results;
}
This will work, however, you will lose all relationship to the database context. This means if you update the returned values, it will not stick it back into the database.
Also, just to repeat my comment, returning more columns (with the exception of byte arrays) does not necessarily mean longer execution time. Returning a lot of rows means more execution time. Your function is returning every single customer in the database, which when your system grows, will start to hang your program, even with the reduced amount of columns.

You are selecting to an anonymous type, which is not a Customer.
If you want to do (sort of) this, you can write it like this:
return db.Customers.Select(x => new Customer { Name = x.CustName, Email = x.CustEmail, Address = x.CustAddress, ContactNo = x.ContactNo }).ToList();
This assumes the properties on your Customer object are what I called them.
** EDIT ** Per your comment,
If you want to return a subset of the table, you can do one of two things:
Return the translated form of Customer as I specified above, or:
Create a new class for your business layer that only has only those four fields, and change your method to return a List<ShrunkenCustomer> (assuming ShunkenCustomer is the name that you choose for your new class.)

GetAllCust() is supposed to return a List of Customer, Select New will create a list of Anonymous Types, you need to return a list of Customer from your query.
try:
var results = db.Customers.Select( new Customer{CustName = x.CustName}).ToList(); //include other fields

I guess Customer is a class you have defined yourself?
The my suggestion would be to do something like the following:
var results = db.Customers.Select(x => new Customer(x.Custname, x.CustEmail, x.CustAddress, x.CustContactNo)).ToList();
The reason is that you are trying to return a list of Customer but the results from your link is an anonymous class containing those four values.
This would of course require that you have a constructor that takes those four values.

Basically whatever u got in var type, loop on that and store it in list<> object then loop and achieve ur target.Here I m posting code for Master details.
List obj = new List();
var orderlist = (from a in db.Order_Master
join b in db.UserAccounts on a.User_Id equals b.Id into abc
from b in abc.DefaultIfEmpty()
select new
{
Order_Id = a.Order_Id,
User_Name = b.FirstName,
Order_Date = a.Order_Date,
Tot_Qty = a.Tot_Qty,
Tot_Price = a.Tot_Price,
Order_Status = a.Order_Status,
Payment_Mode = a.Payment_Mode,
Address_Id = a.Address_Id
});
List<MasterOrder> ob = new List<MasterOrder>();
foreach (var item in orderlist)
{
MasterOrder clr = new MasterOrder();
clr.Order_Id = item.Order_Id;
clr.User_Name = item.User_Name;
clr.Order_Date = item.Order_Date;
clr.Tot_Qty = item.Tot_Qty;
clr.Tot_Price = item.Tot_Price;
clr.Order_Status = item.Order_Status;
clr.Payment_Mode = item.Payment_Mode;
clr.Address_Id = item.Address_Id;
ob.Add(clr);
}
using(ecom_storeEntities en=new ecom_storeEntities())
{
var Masterlist = en.Order_Master.OrderByDescending(a => a.Order_Id).ToList();
foreach (var i in ob)
{
var Child = en.Order_Child.Where(a => a.Order_Id==i.Order_Id).ToList();
obj.Add(new OrderMasterChild
{
Master = i,
Childs = Child
});
}
}