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Applying a function to every row of a table using dplyr?
...it reflects the fact that when you're doing row wise operations you're actually working with tuples from a list of vectors (the columns in a dataframe).
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Method overloading in Objective-C?
...sign pattern)
Here's a simple example on how function overloading works:
__attribute__((overloadable)) float area(Circle * this)
{
return M_PI*this.radius*this.radius;
}
__attribute__((overloadable)) float area(Rectangle * this)
{
return this.w*this.h;
}
//...
//In your Obj-C methods you...
How to tell PowerShell to wait for each command to end before starting the next?
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Normally, for internal commands PowerShell does wait before starting the next command. One exception to this rule is external Windows subsystem based EXE. The first trick is to pipeline to Out-Null like so:
Notepad.exe | Out-N...
How would you access Object properties from within an object method? [closed]
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PHP offers a myriad of ways to handle this, including magic methods __get and __set, but I prefer explicit getters and setters. Here's why:
Validation can be placed in setters (and getters for that matter)
Intellisense works with explicit methods
No question whether a property is read only,...
Select columns from result set of stored procedure
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Here's a link to a pretty good document explaining all the different ways to solve your problem (although a lot of them can't be used since you can't modify the existing stored procedure.)
How to Share Data Between Stored Procedures
Gulzar's answer will work (it is document...
What is the difference between concurrency and parallelism?
What is the difference between concurrency and parallelism?
37 Answers
37
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Undoing a 'git push'
... highly dangerous if you are working in a shared repo. As a best practice, all commits pushed to a remote repo that is shared should be considered 'immutable'. Use 'git revert' instead: kernel.org/pub/software/scm/git/docs/…
– Saboosh
Jan 13 '12 at 20:47
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How does this milw0rm heap spraying exploit work?
I usually do not have difficulty to read JavaScript code but for this one I can’t figure out the logic. The code is from an exploit that has been published 4 days ago. You can find it at milw0rm .
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How do you execute an arbitrary native command from a string?
...her path\file.ext"'
iex "& $command"
Likely, you could handle nearly all cases by detecting if the first character of the command string is ", like in this naive implementation:
function myeval($command) {
if ($command[0] -eq '"') { iex "& $command" }
else { iex $command }
}
But...
iphone Core Data Unresolved error while saving
...conflict with the old model implementation.
Edit:
I almost forgot here's all the error codes that Core Data spits out:
Core Data Constants Reference
I had trouble with this before and I realised I unchecked the correct optional box. Such trouble finding out the problem. Good luck.
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