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C++中智能指针的设计和使用 - C/C++ - 清泛网 - 专注C/C++及内核技术
...释放对象拥有权限、引用计数等，控制权转移等）。auto_ptr 即是一种常见的智能指针。
智能指针通常用类模板实现：
template <class T>
class smartpointer
{
private:
T *_ptr;
public:
smartpointer(T *p) : _ptr(p) //构造函数
{
}
T& oper...
Remove rows with duplicate indices (Pandas DataFrame and TimeSeries)
...Pandas Index itself:
df3 = df3[~df3.index.duplicated(keep='first')]
While all the other methods work, the currently accepted answer is by far the least performant for the provided example. Furthermore, while the groupby method is only slightly less performant, I find the duplicated method to be mor...
trying to animate a constraint in swift
...t tapGesture = UITapGestureRecognizer(target: self, action: #selector(doIt(_:)))
textView.addGestureRecognizer(tapGesture)
}
@objc func doIt(_ sender: UITapGestureRecognizer) {
heightConstraint.constant = heightConstraint.constant == 50 ? 150 : 50
UIView.animate(with...
How can you find and replace text in a file using the Windows command-line environment?
... comes with PowerShell built-in. Here is the script I used to find/replace all instances of text in a file:
powershell -Command "(gc myFile.txt) -replace 'foo', 'bar' | Out-File -encoding ASCII myFile.txt"
To explain it:
powershell starts up powershell.exe, which is included in Windows 7
-Command ...
Naming convention for unique constraint
...primary key and foreign key have commonly used and obvious conventions ( PK_Table and FK_Table_ReferencedTable , respectively). The IX_Table_Column naming for indexes is also fairly standard.
...
Importing CommonCrypto in a Swift framework
...mething a little simpler and more robust is to create an Aggregate target called "CommonCryptoModuleMap" with a Run Script phase to generate the module map automatically and with the correct Xcode/SDK path:
The Run Script phase should contain this bash:
# This if-statement means we'll only run ...
How to split long commands over multiple lines in PowerShell
...loy.exe" `
-verb:sync `
-source:contentPath="c:\workspace\xxx\master\Build\_PublishedWebsites\xxx.Web" `
-dest:contentPath="c:\websites\xxx\wwwroot,computerName=192.168.1.1,username=administrator,password=xxx"
White space matters. The required format is Space`Enter.
...
How to reset sequence in postgres and fill id column with new data?
... This might cause duplicate ids. To prevent this, you can first set all to very high values: UPDATE t SET idcolumn=1000000+ nextval('seq'); then run the above script.
– tahagh
Nov 28 '13 at 13:15
...
Distinct not working with LINQ to Objects
...
LINQ Distinct is not that smart when it comes to custom objects.
All it does is look at your list and see that it has two different objects (it doesn't care that they have the same values for the member fields).
One workaround is to implement the IEquatable interface as shown here.
If yo...
Microsoft CDN for jQuery or Google CDN? [closed]
Does it actually matter which CDN you use to link to your jquery file or any javascript file for that matter. Is one potentially faster than the other? What other factors could play a role in which cdn you decide to use? I know that Microsoft, Yahoo, and Google all have CDN's now.
...