Tagged Questions
15
votes
3answers
444 views
Lambda Scope Clarification
Why does my parameter x behave so erratically?
Example 1 - Doesn't exist in the current context.
Example 2 - Cannot reuse x because it's defined in a 'child' scope.
Example 3 - Fine. This is the ...
13
votes
10answers
10k views
Beginner book for Lambda Expression [closed]
I'm a beginner in lambda, I would like to know your suggestion for the best tutorial ebook/video on using lambda expression. Thank you
10
votes
2answers
148 views
How to cast lambdas?
I'd like a family of functions to be kept in a dictionary that derive from some base type (lets call the base class "object" for example sake). So, it it possible to keep f1 in f2?
Func<bool> ...
7
votes
2answers
2k views
How to return value with anonymous method?
This fails
string temp = () => {return "test";};
with the error
Cannot convert lambda expression to type 'string' because it is not a delegate type
What does the error mean and how can I ...
5
votes
4answers
219 views
linq ambiguity on where and select
Today I ran into an issue with LINQ to objects (not SQL) that popped up due to a typo. I had a .Select one place and a .Where in another place. I was expecting same result but they are showing ...
5
votes
4answers
2k views
How to get last x records from a list with Lamdba
I have as List of strings with where i remove each duplicates, now I want to filter it even more to get the last 5 records. How can I do this?
What I got so far
List<string> query = ...
5
votes
2answers
2k views
How to “let” in lambda expression?
How can I rewrite this linq query to Entity on with lambda expression?
I want to use let keyword or an equivalent in my lambda expression.
var results = from store in Stores
let ...
5
votes
4answers
304 views
Lambda expression “IN” operator Exists?
I'm looking for to build the Lambda expression like the below
IQueryable<Object> queryEntity =
_db.Projects.Where(Project=>Project.Id.IN(1,2,3,4));
I don't find any IN ...
5
votes
1answer
241 views
Creating a Func<> dynamically - Lambdas vs. Expression trees
Here is some code to return a linear function (y=ax+b).
public static Func<double, double> LinearFunc(double slope, double offset)
{
return d => d * slope + offset;
}
I could do the ...
5
votes
1answer
4k views
Lambda expressions - set the value of one property in a collection of objects based on the value of another property in the collection
I'm new to lambda expressions and looking to leverage the syntax to set the value of one property in a collection based on another value in a collection
Typically I would do a loop:
class Item
{
...
4
votes
4answers
143 views
General Lambda syntax question
So I seem to be confident that the following 2 statements are the same
List<object> values = new List<object>();
values.ForEach(value => ...
4
votes
3answers
7k views
Equivalent of SQL Between Statement Using Linq or a Lambda expression
Don't think this is a repost, difficult to search for the word between because it is used in everything (like searching for AND).
I want to filter a list based on a date range.
I have a list with ...
4
votes
3answers
87 views
Why are lambdas convertible to expressions but method groups are not?
LINQPad example:
void Main()
{
One(i => PrintInteger(i));
One(PrintInteger);
Two(i => PrintInteger(i));
// Two(PrintInteger); - won't compile
}
static void ...
4
votes
1answer
1k views
Join 3 tables with a lambda expression?
I basically want the following sql query as a lambda expression:
SELECT studentname, coursename, grade
FROM student S, course C, grade G
WHERE S.id = G.studentid AND C.coursecode = G.coursecode AND ...
4
votes
2answers
358 views
Why doesn't HasFlag() work in Linq to Entities?
I have a flag e.g.
[Flags]
public enum DaysOfTheWeek
{
Monday = 1,
Tuesday = 2,
Wednesday = 4,
Thursday = 8,
Friday = 16,
Saturday = 32,
Sunday = 64
}
If I want to use ...
