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Select rows of a matrix that meet a condition
... How does this work if you don't want to specify the column names at all but want to work over all columns in the matrix?
– user5359531
Jul 22 '16 at 22:54
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How to do SELECT COUNT(*) GROUP BY and ORDER BY in Django?
I'm using a transaction model to keep track all the events going through the system
2 Answers
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docker mounting volumes on host
...independent of the container's life cycle. Docker therefore never automatically delete volumes when you remove a container, nor will it "garbage collect" volumes that are no longer referenced by a container." One of these statements must be wrong.
– mc0e
May 6...
Convert to absolute value in Objective-C
...), fabsf(float), fabs(double), or fabsl(long double).
Those functions are all part of the C standard library, and so are present both in Objective-C and plain C (and are generally available in C++ programs too.)
(Alas, there is no habs(short) function. Or scabs(signed char) for that matter...)
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jQuery - checkbox enable/disable
...ve a bunch of checkboxes like this. If the "Check Me" checkbox is checked, all the other 3 checkboxes should be enabled, else they should be disabled. How can I do this using jQuery?
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How to “warm-up” Entity Framework? When does it get “cold”?
... help increase performance. However with EF5 it isn't necessary to compile all your queries since EF will auto-compile queries itself. The only problem is that these queries can get lost when the cache is swept. So you still want to hold references to your own compiled queries for those that are occ...
Changing case in Vim
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Visual select the text, then U for uppercase or u for lowercase. To swap all casing in a visual selection, press ~ (tilde).
Without using a visual selection, gU<motion> will make the characters in motion uppercase, or use gu<motion> for lowercase.
For more of these, see Section 3 in ...
When to make a type non-movable in C++11?
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Herb's answer (before it was edited) actually gave a good example of a type which shouldn't be movable: std::mutex.
The OS's native mutex type (e.g. pthread_mutex_t on POSIX platforms) might not be "location invariant" meaning the object's address is part of its va...
Using CSS to insert text
...
It is, but requires a CSS2 capable browser (all major browsers, IE8+).
.OwnerJoe:before {
content: "Joe's Task:";
}
But I would rather recommend using Javascript for this. With jQuery:
$('.OwnerJoe').each(function() {
$(this).before($('<span>').text("Joe'...
git remote prune – didn't show as many pruned branches as I expected
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When you use git push origin :staleStuff, it automatically removes origin/staleStuff, so when you ran git remote prune origin, you have pruned some branch that was removed by someone else. It's more likely that your co-workers now need to run git prune to get rid of branches you...