大约有 44,000 项符合查询结果（耗时：0.0588秒） [XML]
Performance surprise with “as” and nullable types
...a few machine code instructions. The cast is also easy, the JIT compiler knows the location of the value bits in the object and uses them directly. No copying or conversion occurs, all machine code is inline and takes but about a dozen instructions. This needed to be really efficient back in .NET...
Is there a range class in C++11 for use with range based for loops?
...ace. range-v3 was always sort-of the reference implementation I'd say. But now I believe the basic range stuff has also recently been voted into C++20, so we will indeed get it in std:: soon! :-)
– Ela782
Jan 3 '19 at 11:56
...
Difference between one-to-many and many-to-one relationship
...
Maybe database relationships now?
– fragorl
Jul 27 '17 at 1:00
add a comment
|
...
Importing variables from another file?
...iables from file1 without flooding file2's namespace, use:
import file1
#now use file1.x1, file2.x2, ... to access those variables
To import all variables from file1 to file2's namespace( not recommended):
from file1 import *
#now use x1, x2..
From the docs:
While it is valid to use from ...
What is the difference between ${var}, “$var”, and “${var}” in the Bash shell?
...introduction to quoting in Bash.
Arrays ($var vs. $var[@] vs. ${var[@]})
Now for your array. According to the bash manual:
Referencing an array variable without a subscript is equivalent to referencing the array with a subscript of 0.
In other words, if you don't supply an index with [], you...
Non-static variable cannot be referenced from a static context
... class and an instance of that class. If you see a car on the street, you know immediately that it's a car even if you can't see which model or type. This is because you compare what you see with the class "car". The class contains which is similar to all cars. Think of it as a template or an idea.
...
Can javax.persistence.Query.getResultList() return null?
...t it right?
No matter what, I would code defensively and check for null.
Now the big question: should we treat "null" and an empty List as synonymous? This is where the specs should help us, and don't.
My guess is that a null return (if indeed it could happen) would be equivalent to "I didn't un...
Razor-based view doesn't see referenced assemblies
...ssemblies section of the root web.config file fixed the issue. The section now looks like:
<system.web>
<compilation debug="true" targetFramework="4.0">
<assemblies>
<add assembly="System.Web.Abstractions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3...
Python vs Bash - In which kind of tasks each one outruns the other performance-wise? [closed]
...lly runs a short Bash script. That script, either directly or indirectly, knows where all the files needed are and sets variables and command line parameters, finally calling the program. That's a shell's simplest use.
Linux as we know it however would hardly be Linux without the thousands of shell...
Are duplicate keys allowed in the definition of binary search trees?
...se problems. Imagine your tree rule is this:
left < root <= right
Now imagine a simple tree whose root is 5, left child is nil, and right child is 5. If you do a left rotation on the root you end up with a 5 in the left child and a 5 in the root with the right child being nil. Now somethi...