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What is the purpose of setting a key in data.table?
...e other vignettes that we plan to.
I've updated this answer again (Feb 2016) in light of the new on= feature that allows ad-hoc joins as well. See history for earlier (outdated) answers.
What exactly does setkey(DT, a, b) do?
It does two things:
reorders the rows of the data.table DT by the...
How to Reverse Fragment Animations on BackStack?
...wered Jun 4 '12 at 18:56
user742030user742030
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How to convert date to timestamp?
I want to convert date to timestamp, my input is 26-02-2012 . I used
13 Answers
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Fastest way to determine if an integer is between two integers (inclusive) with known sets of values
...e interval to the point of origin and checks if number is in the interval [0, D], where D = upper - lower. If number below lower bound: negative, and if above upper bound: larger than D.
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Firefox Web Console Disabled?
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160
This happens when the page itself defines a global variable called console, for example. If the...
MySQL Results as comma separated list
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250
You can use GROUP_CONCAT to perform that, e.g. something like
SELECT p.id, p.name, GROUP_CONCAT...
Index of Currently Selected Row in DataGridView
...Row of a DataGridView ? I don't want the Row object, I want the index (0 .. n).
12 Answers
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Can you avoid Gson converting “” into unicode escape sequences?
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answered Nov 10 '10 at 17:32
BalusCBalusC
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How do I fix “for loop initial declaration used outside C99 mode” GCC error?
...o.h>
int main() {
int i;
/* for loop execution */
for (i = 10; i < 20; i++) {
printf("i: %d\n", i);
}
return 0;
}
Read more on for loops in C here.
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What C++ Smart Pointer Implementations are available?
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C++03
std::auto_ptr - Perhaps one of the originals it suffered from first draft syndrome only providing limited garbage collection facilities. The first downside being that it calls delete upon destruction making them unaccepta...