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Can “using” with more than one resource cause a resource leak?
...riable.
The spec (§8.13) says:
When a resource-acquisition takes the form of a
local-variable-declaration, it is possible to acquire multiple
resources of a given type. A using statement of the form
using (ResourceType r1 = e1, r2 = e2, ..., rN = eN) statement
is precisely
equiva...
What's is the difference between include and extend in use case diagram?
...luding the "login" steps being a good candidate for a include. Those steps form a use case own their own, and should be linked to the others use cases by post-conditions -> pre-conditions.
– Bruno Brant
Jan 20 '15 at 17:10
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PHP $_SERVER['HTTP_HOST'] vs. $_SERVER['SERVER_NAME'], am I understanding the man pages correctly?
...o, array_key_exists is more scalable compared to in_array that has O(n) performance.
– Pacerier
Mar 5 '15 at 23:43
2
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In Matplotlib, what does the argument mean in fig.add_subplot(111)?
...grid, first subplot" and "234" means "2x3 grid, 4th subplot".
Alternative form for add_subplot(111) is add_subplot(1, 1, 1).
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In Django, how does one filter a QuerySet with dynamic field lookups?
...nt expansion may be used to solve this problem:
kwargs = {
'{0}__{1}'.format('name', 'startswith'): 'A',
'{0}__{1}'.format('name', 'endswith'): 'Z'
}
Person.objects.filter(**kwargs)
This is a very common and useful Python idiom.
...
How to check file MIME type with javascript before upload?
...that the real validation still has to be done on server side. I want to perform a client side checking to avoid unnecessary wastage of server resource.
...
Hidden features of mod_rewrite
...file. if you have access to httpd.conf, placing rules here will offer a performance benefit (as the rules are processed once, as opposed to each time the .htaccess file is called).
Logging mod_rewrite requests
Logging may be enabled from within the httpd.conf file (including <Virtual Host>):...
Java Generics (Wildcards)
...
In general,
If a structure contains elements with a type of the form ? extends E, we can get elements out of the structure, but we cannot put
elements into the structure
List<Integer> ints = new ArrayList<Integer>();
ints.add(1);
ints.add(2);
List<? extends Number> n...
Mongodb Explain for Aggregation framework
...ns
As at MongoDB 3.4, the Aggregation Framework explain option provides information on how a pipeline is processed but does not support the same level of detail as the executionStats mode for a find() query. If you are focused on optimizing initial query execution you will likely find it beneficial...
Shell equality operators (=, ==, -eq)
...riting a #!/bin/bash script then I recommend using [[ instead. The doubled form has more features, more natural syntax, and fewer gotchas that will trip you up. Double quotes are no longer required around $a, for one:
$ [[ $a == foo ]]; echo "$?" # bash specific
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See also:
What's the diff...