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What is the volatile keyword useful for?
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volatile has semantics for memory visibility. Basically, the value of a volatile field becomes visible to all readers (other threads in particular) after a write operation completes on it. Without volatile, readers could see some non-updated value.
To answer your question: Y...
Vagrant error : Failed to mount folders in Linux guest
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The plugin vagrant-vbguest solved my problem:
$ vagrant plugin install vagrant-vbguest
Output:
$ vagrant reload
==> default: Attempting graceful shutdown of VM...
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==> default: Machine booted and ready!
GuestAdditions 4.3.12 running --- OK.
==> default: Checking for guest addi...
java.util.regex - importance of Pattern.compile()?
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The compile() method is always called at some point; it's the only way to create a Pattern object. So the question is really, why should you call it explicitly? One reason is that you need a reference to the Matcher object so you can use its methods, like...
How to read a large file line by line?
...e line from the file.
echo $file->fgets();
}
// Unset the file to call __destruct(), closing the file handle.
$file = null;
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Wait for a void async method
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await Task.Run(() => An_async_void_method_I_can_not_modify_now())
– themefield
Mar 12 '19 at 21:46
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How do I get the base URL with PHP?
... XAMPP on Windows Vista. In my development, I have http://127.0.0.1/test_website/ .
22 Answers
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Check if something is (not) in a list in Python
... @nightcracker That makes no sense as A not in B is reduced to doing not B.__contains__(A) which is the same as what not A in B is reduced to which is not B.__contains__(A).
– Dan D.
May 2 '12 at 0:33
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Explicitly select items from a list or tuple
... myBigList[i] for i in [87, 342, 217, 998, 500] ]
20.6 usec: map(myBigList.__getitem__, (87, 342, 217, 998, 500))
22.7 usec: itemgetter(87, 342, 217, 998, 500)(myBigList)
24.6 usec: list( myBigList[i] for i in [87, 342, 217, 998, 500] )
Note that in Python 3, the 1st was changed to be the same as ...
How can I generate a unique ID in Python? [duplicate]
...in newer versions, but most people probably don't have that yet, so I generally avoid this module. Caused me major headaches with listen sockets...
– Glenn Maynard
Jul 31 '09 at 3:14
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How to 'bulk update' with Django?
...ings like incrementing rows:
from django.db.models import F
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
See the documentation.
However, note that:
This won't use ModelClass.save method (so if you have some logic inside it won't be triggered).
No django signals will be emitte...