大约有 40,000 项符合查询结果（耗时：0.0364秒） [XML]
The relationship could not be changed because one or more of the foreign-key properties is non-nulla
...iginal parent including the child item collection
var originalParent = _dbContext.ParentItems
.Where(p => p.ID == parent.ID)
.Include(p => p.ChildItems)
.SingleOrDefault();
// We assume that the parent is still in the DB and don't check for null
// Update s...
What are some uses of decltype(auto)?
...p;&
auto x6a = { 1, 2 }; // decltype(x6a) is std::initializer_list<int>
decltype(auto) x6d = { 1, 2 }; // error, { 1, 2 } is not an expression
auto *x7a = &i; // decltype(x7a) is int*
decltype(auto)*x7d = &i; // error, declared type is not plain declt...
What can you do in MSIL that you cannot do in C# or VB.NET? [closed]
...etty much all over the place. Examine the IL for this: "let print x = print_any x".
– MichaelGG
Feb 24 '09 at 23:22
1
...
In PHP, can you instantiate an object and call a method on the same line?
...So, if you declared a class like this :
class Test {
public function __construct($param) {
$this->_var = $param;
}
public function myMethod() {
return $this->_var * 2;
}
protected $_var;
}
You can then declare a function that returns an instance of that ...
Read only the first line of a file?
...od (Python 2 docs, Python 3 docs):
with open('myfile.txt') as f:
first_line = f.readline()
Some notes:
As noted in the docs, unless it is the only line in the file, the string returned from f.readline() will contain a trailing newline. You may wish to use f.readline().strip() instead to rem...
Is there a performance difference between i++ and ++i in C++?
... this->data += 1;
return *this;
}
Foo Foo::operator++(int ignored_dummy_value) // called for i++
{
Foo tmp(*this); // variable "tmp" cannot be optimized away by the compiler
++(*this);
return tmp;
}
Since the compiler isn't generating code, but just calling an operator++ ...
How to write log base(2) in c/c++
...
#define M_LOG2E 1.44269504088896340736 // log2(e)
inline long double log2(const long double x){
return log(x) * M_LOG2E;
}
(multiplication may be faster than division)
...
Cloning an Object in Node.js
...ion is now marked as deprecated in the documentation of Node.js:
The util._extend() method was never intended to be used outside of internal Node.js modules. The community found and used it anyway.
It is deprecated and should not be used in new code. JavaScript comes with very similar built-in func...
Which commit has this blob?
...
Here it is as a shell script – short and sweet, but slow:
#!/bin/sh
obj_name="$1"
shift
git log "$@" --pretty=format:'%T %h %s' \
| while read tree commit subject ; do
if git ls-tree -r $tree | grep -q "$obj_name" ; then
echo $commit "$subject"
fi
done
And an optimised version ...
Print list without brackets in a single row
...
@FredrickGauss if you add from __future__ import print_function it'll work in python 2 as well.
– Anthony Sottile
Aug 26 '17 at 22:07
1
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