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How do I check for C++11 support?
...t have (partial) compiler-level support versus a standard C++ library with all the C++11 changes.
So Boost's defines mentioned in another answer remain the only sane way to figure out if there is, for example, support for C++11 threads and other specific parts of the standard.
...
Capturing Groups From a Grep RegEx
...egex="[0-9]+_([a-z]+)_[0-9a-z]*"
for f in $files # unquoted in order to allow the glob to expand
do
if [[ $f =~ $regex ]]
then
name="${BASH_REMATCH[1]}"
echo "${name}.jpg" # concatenate strings
name="${name}.jpg" # same thing stored in a variable
else
...
How do I filter ForeignKey choices in a Django ModelForm?
... can populate the validation data by making using the super(...).__init__ call in your overridden method. If you are making several of these queryset changes its a lot more elegant to package them by overriding the init method.
– michael
Aug 7 '09 at 4:53
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Is there a difference between “==” and “is”?
... a
True
In your case, the second test only works because Python caches small integer objects, which is an implementation detail. For larger integers, this does not work:
>>> 1000 is 10**3
False
>>> 1000 == 10**3
True
The same holds true for string literals:
>>> "a" i...
Performance difference for control structures 'for' and 'foreach' in C#
...t will depend on whether you're doing any real work in the loop. In almost all cases, the difference to performance won't be significant, but the difference to readability favours the foreach loop.
I'd personally use LINQ to avoid the "if" too:
foreach (var item in list.Where(condition))
{
}
EDI...
What is the meaning of single and double underscore before an object name?
...at least two leading underscores, at most one trailing underscore) is textually replaced with _classname__spam, where classname is the current class name with leading underscore(s) stripped. This mangling is done without regard to the syntactic position of the identifier, so it can be used to define...
node.js global variables?
...
Globals are generally to be avoided, but if you really want to use them. The 3 statements below are all equivalent and will assign a var to the global scope: GLOBAL._ = require('underscore'); global._ = require('underscore'); _ = require('und...
Is there a way to access method arguments in Ruby?
... "#{arg} = #{eval arg}" }.join(', ')
Note: since this answer was originally written, in current versions of Ruby eval can no longer be called with a symbol. To address this, an explicit to_s has been added when building the list of parameter names i.e. parameters.map { |arg| arg[1].to_s }
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python multithreading wait till all threads finished
...oin method of Thread object in the end of the script.
t1 = Thread(target=call_script, args=(scriptA + argumentsA))
t2 = Thread(target=call_script, args=(scriptA + argumentsB))
t3 = Thread(target=call_script, args=(scriptA + argumentsC))
t1.start()
t2.start()
t3.start()
t1.join()
t2.join()
t3.join...
How do I read any request header in PHP
...
IF: you only need a single header, instead of all headers, the quickest method is:
<?php
// Replace XXXXXX_XXXX with the name of the header you need in UPPERCASE (and with '-' replaced by '_')
$headerStringValue = $_SERVER['HTTP_XXXXXX_XXXX'];
ELSE IF: you run PHP...