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What does .SD stand for in data.table in R
.SD looks useful but I do not really know what I am doing with it. What does it stand for? Why is there a preceding period (full stop). What is happening when I use it?
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try/catch + using, right syntax
...follow
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edited Jan 4 '11 at 4:05
answered Jan 4 '11 at 3:58
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Why can I access private variables in the copy constructor?
I have learned that I can never access a private variable, only with a get-function in the class. But then why can I access it in the copy constructor?
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Data structure: insert, remove, contains, get random element, all at O(1)
...e keys are the elements in the data structure, and the values are their positions in the array.
insert(value): append the value to array and let i be its index in A. Set H[value]=i.
remove(value): We are going to replace the cell that contains value in A with the last element in A. let d be the la...
Difference between static memory allocation and dynamic memory allocation
... when the program starts. The size is fixed when the program is created. It applies to global variables, file scope variables, and variables qualified with static defined inside functions.
Automatic memory allocation occurs for (non-static) variables defined inside functions, and is usually store...
Copy object values in Visual Studio debug mode
In Visual Studio debug mode it's possible to hover over variables to show their value and then right-click to "Copy", "Copy Expression" or "Copy Value".
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oh-my-zsh slow, but only for certain Git repo
I recently started using Zsh and it's awesome. Unfortunately, for the project I consider my "main" project, everything is slow. What I mean is that every time I run a command - ls , for example - there's about a five-second delay between the time the command is executed and the time I can use the t...
How to export DataTable to Excel
... to Excel in C#? I am using Windows Forms. The DataTable is associated with a DataGridView control. I have to export records of DataTable to Excel.
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How to resolve “Error: bad index – Fatal: index file corrupt” when using Git
After git init , I added and committed a few files, made some changes, added and committed. Set up the git daemon (running under Cygwin on WinXP) and cloned the repository once.
Now, I get this error with the cloned repository:
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What is your favorite C programming trick? [closed]
...ues) {
while(*values) {
x = *values++;
/* do whatever with x */
}
}
func((type[]){val1,val2,val3,val4,0});
Static linked lists
int main() {
struct llist { int a; struct llist* next;};
#define cons(x,y) (struct llist[]){{x,y}}
struct llist *list=cons(1, cons(2,...