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How important is the order of columns in indexes?
... Also keep in mind, suppose your Index is like the picture above, and your query filters on column1 and column2, but column2 is more unique and what you really want to filter on is actually column2, then its more beneficial to just have a index where column 2 is first. This may seem counte...
How to apply multiple styles in WPF
...xists on the base class of the element that I want to apply two styles to. And, in the second style which is based on the base style, I set another property.
So, the idea here ... is if you can somehow separate the properties that you want to set ... according the inheritance hierarchy of the eleme...
How to determine if a number is a prime with regex?
...
You said you understand this part, but just to emphasize, the String generated has a length equal to the number supplied. So the string has three characters if and only if n == 3.
.?
The first part of the regex says, "any character, zero or o...
Checking if an Android application is running in the background
... completely reliable:
The right solution (credits go to Dan, CommonsWare and NeTeInStEiN)
Track visibility of your application by yourself using Activity.onPause, Activity.onResume methods. Store "visibility" status in some other class. Good choices are your own implementation of the Application o...
How to close Android application?
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Android has a mechanism in place to close an application safely per its documentation. In the last Activity that is exited (usually the main Activity that first came up when the application started) just place a couple of li...
What would a “frozen dict” be?
...self._d[key]
def __hash__(self):
# It would have been simpler and maybe more obvious to
# use hash(tuple(sorted(self._d.iteritems()))) from this discussion
# so far, but this solution is O(n). I don't know what kind of
# n we are going to run into, but sometime...
Why is String.chars() a stream of ints in Java 8?
...d, the design decision behind this was to prevent the explosion of methods and classes.
Still, personally I think this was a very bad decision, and there should, given they do not want to make CharStream, which is reasonable, different methods instead of chars(), I would think of:
Stream<Chara...
val-mutable versus var-immutable in Scala
...that means is that, if I have an expression "e", I could make a val x = e, and replace e with x. This is the property that mutability break. Whenever you need to make a design decision, maximize for referential transparency.
As a practical matter, a method-local var is the safest var that exists, s...
When should I use jQuery deferred's “then” method and when should I use the “pipe” method?
...d. The deferred.then() method, which replaces it, should be used instead.
and
As of jQuery 1.8, the deferred.then() method returns a new promise that can filter the status and values of a deferred through a function, replacing the now-deprecated deferred.pipe() method.
The examples below might st...
What use is find_package() if you need to specify CMAKE_MODULE_PATH anyway?
...ing CMake. Now the software has a few dependencies. I compiled them myself and installed them on my system.
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