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How to determine the Boost version on a system?
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Boost Informational Macros. You need: BOOST_VERSION
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I want to get the type of a variable at runtime
...ific type, such as this:
val x: Any = 5
def f[T](v: T) = v match {
case _: Int => "Int"
case _: String => "String"
case _ => "Unknown"
}
f(x)
Here it doesn't matter what is the type of the variable, Any. What matters, what is checked is the type of 5, the value. In fact,...
Markdown open a new window link [duplicate]
...always use HTML inside markdown:
<a href="http://example.com/" target="_blank">example</a>
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Rounding up to next power of 2
...an be used to compute log2 very efficiently. See en.wikipedia.org/wiki/Find_first_set
– Simon
Oct 4 '13 at 21:57
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Django DB Settings 'Improperly Configured' Error
...--settings=mysite.settings (or whatever settings module you use)
Set DJANGO_SETTINGS_MODULE environment variable in your OS to mysite.settings
(This is removed in Django 1.6) Use setup_environ in the python interpreter:
from django.core.management import setup_environ
from mysite import settings
s...
Concatenating two one-dimensional NumPy arrays
...There are several possibilities for concatenating 1D arrays, e.g.,
numpy.r_[a, a],
numpy.stack([a, a]).reshape(-1),
numpy.hstack([a, a]),
numpy.concatenate([a, a])
All those options are equally fast for large arrays; for small ones, concatenate has a slight edge:
The plot was created with perf...
sys.argv[1] meaning in script
... prints the number of arguments, using the len function on the list.
from __future__ import print_function
import sys
print(sys.argv, len(sys.argv))
The script requires Python 2.6 or later. If you call this script print_args.py, you can invoke it with different arguments to see what happens.
>...
How can I add a key/value pair to a JavaScript object?
...ush(). For more info check the docs, they have some great examples there.
_.merge (Lodash only)
The second object will overwrite or add to the base object.
undefined values are not copied.
var obj = {key1: "value1", key2: "value2"};
var obj2 = {key2:"value4", key3: "value3", key4: undefined};
_.m...
In Python, using argparse, allow only positive integers
...still need to define an actual method that decides this for you:
def check_positive(value):
ivalue = int(value)
if ivalue <= 0:
raise argparse.ArgumentTypeError("%s is an invalid positive int value" % value)
return ivalue
parser = argparse.ArgumentParser(...)
parser.add_argu...
ASP.NET MVC - Attaching an entity of type 'MODELNAME' failed because another entity of the same type
... only fields except entity id worked fine: var entity = context.Find(entity_id); entity.someProperty = newValue; context.Entry(entity).Property(x => x.someProperty).IsModified = true; context.SaveChanges();
– Anton Lyhin
Dec 10 '15 at 22:34
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