大约有 16,000 项符合查询结果（耗时：0.0341秒） [XML]
Group by in LINQ
...utely - you basically want:
var results = from p in persons
group p.car by p.PersonId into g
select new { PersonId = g.Key, Cars = g.ToList() };
Or as a non-query expression:
var results = persons.GroupBy(
p => p.PersonId,
p => p.car,
(key, g) =>...
Awaiting multiple Tasks with different results
...wait:
var catTask = FeedCat();
var houseTask = SellHouse();
var carTask = BuyCar();
await Task.WhenAll(catTask, houseTask, carTask);
var cat = await catTask;
var house = await houseTask;
var car = await carTask;
You can also use Task.Result (since you know by this point they have all completed ...
Populating a razor dropdownlist from a List in MVC
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You can separate out your business logic into a viewmodel, so your view has cleaner separation.
First create a viewmodel to store the Id the user will select along with a list of items that will appear in the DropDown.
ViewModel:
public class UserR...
How to list variables declared in script in bash?
In my script in bash, there are lot of variables, and I have to make something to save them to file.
My question is how to list all variables declared in my script and get list like this:
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Why is unsigned integer overflow defined behavior but signed integer overflow isn't?
Unsigned integer overflow is well defined by both the C and C++ standards. For example, the C99 standard ( §6.2.5/9 ) states
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Fastest way to replace NAs in a large data.table
I have a large data.table , with many missing values scattered throughout its ~200k rows and 200 columns. I would like to re code those NA values to zeros as efficiently as possible.
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In Python, how to display current time in readable format
...me
time.ctime() # 'Mon Oct 18 13:35:29 2010'
time.strftime('%l:%M%p %Z on %b %d, %Y') # ' 1:36PM EDT on Oct 18, 2010'
time.strftime('%l:%M%p %z on %b %d, %Y') # ' 1:36PM EST on Oct 18, 2010'
share
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Selecting the last value of a column
I have a spreadsheet with some values in column G. Some cells are empty in between, and I need to get the last value from that column into another cell.
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How to get client's IP address using JavaScript?
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I would use a web service that can return JSON (along with jQuery to make things simpler). Below are all the free active IP lookup services I could find and the information they return. If you know of any more, then please add a comment and ...
How is “=default” different from “{}” for default constructor and destructor?
I originally posted this as a question only about destructors, but now I'm adding consideration of the default constructor. Here's the original question:
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