CODEWITHSUNDEEP
linq
WhoAmI
WhoAmI

Reputation: 1236

Return one Element from List using LINQ

I have a list that contains 3 variables, expense, salary and year. I would like to return all expenses from the list using LINQ. Writing a foreach loop would suffice but I was hoping to archive something more efficient using LINQ.

I'm thinking something like this:

List<Company> ListCompanies = new List<Company>();

Company company1 = new Company() { Expense = 200, Salary = 1000, Year = new DateTime(2014, 1, 1).ToString("yyyy/mm/dd") };
Company company2 = new Company() { Expense = 300, Salary = 800, Year = new DateTime(2014, 2, 1).ToString("yyyy/mm/dd") };
Company company3 = new Company() { Expense = 500, Salary = 1400, Year = new DateTime(2014, 3, 1).ToString("yyyy/mm/dd") };

ListCompanies.Add(company1);
ListCompanies.Add(company2);
ListCompanies.Add(company3);

var Exp = ListCompanies.Where(e => ListCompanies.Contains(e.Expense));

This doesn't work as I'm getting this error:

Argument 1: cannot convert from 'int' to 'Project1.Company

I know I could get the direct values out of a LINQ query like this:

var CompanyName = ListCompanies.Where(cn => cn.Name.Contains("X"));

which would give me all company names that contains "X". Isn't it possible to get all company names in ListConpanies?

Hope I'm not to unclear.

Thanks!

Upvotes: 1

Views: 1808

Answers (4)

Sandeep Kumar
Sandeep Kumar

Reputation: 1543

You are getting the error because you are searching an int Expense in a collection of (Company type) companies so type difference causes the error.

You can select any property from a IEnumerable by using Select extenion Method and it will return IEnumerable.

 var Expenses = ListCompanies.Select(c => c.Expenses);
 var Salaries = ListCompanies.Select(c => c.Salary);
 var Years = ListCompanies.Select(c => c.Year);

These all Expenses, Salaries and Years are of IEnurable type. If you want list from this then you have to call ToList() extension method.

 var Expenses = ListCompanies.Select(c => c.Expenses).ToList();
 var Salaries = ListCompanies.Select(c => c.Salary).ToList();
 var Years = ListCompanies.Select(c => c.Year).ToList();

Upvotes: 1

Konrad Kokosa
Konrad Kokosa

Reputation: 16878

If you want to get all salaries, simply use Select:

var salaries = ListCompanies.Select(e => e.Salary );

Also, you are not right when saying that:

var CompanyName = ListCompanies.Where(cn => cn.Name.Contains("X"));

would give you all company names that contains "X". It will return a IEnumerable<Company> of companies which name contains "X". It might not single but multiple companies. You can then select their salaries by combining Where and Select clauses:

var filteredSalaries = ListCompanies.Where(c => c.Name.Contains("X"))
                                    .Select(c => c.Salary);

Upvotes: 1

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 726579

You can get all salaries into a separate list with a Select:

var allSalaries = ListCompanies.Select(c => c.Salary).ToList();

This produces a list wit {1000, 800, 1400}

If you do not want a list, but wish to iterate over a particular attribute from your list, you can do a Select in a foreach loop:

foreach (var expense in ListCompanies.Select(c => c.Expense)) {
    ...
}

Upvotes: 1

anderas
anderas

Reputation: 5844

To get all salaries, try this:

var salaries = ListCompanies.Select(c => c.Salary);

This will get you an IEnumerable. If desired, you can convert it using ToArray(), ToList()etc.

Upvotes: 1

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