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What is PostgreSQL explain telling me exactly?
...ple, e.g. the cost of the LIMIT is cost=0.00..3.39 and the cost of sequentially scanning post is cost=0.00..15629.12. The first number in the tuple is the startup cost and the second number is the total cost. Because I used EXPLAIN and not EXPLAIN ANALYZE, these costs are estimates, not actual measu...
How can I check for “undefined” in JavaScript? [duplicate]
...
I personally use
myVar === undefined
Warning: Please note that === is used over == and that myVar has been previously declared (not defined).
I do not like typeof myVar === "undefined". I think it is long winded and unnecessar...
What is the difference between `new Object()` and object literal notation?
...rly recognizable as to what is happening, so using new Object(), you are really just typing more and (in theory, if not optimized out by the JavaScript engine) doing an unnecessary function call.
These
person = new Object() /*You should put a semicolon here too.
It's not required, but it is goo...
Difference between Divide and Conquer Algo and Dynamic Programming
...d only once and the result of each sub-problem is stored in a table ( generally implemented as an array or a hash table) for future references. These sub-solutions may be used to obtain the original solution and the technique of storing the sub-problem solutions is known as memoization.
You may thi...
Do browsers parse javascript on every page load?
...een able to dig up. It's worth noting first that although JavaScript is usually considered to be interpreted and run on a VM, this isn't really the case with the modern interpreters, which tend to compile the source directly into machine code (with the exception of IE).
Chrome : V8 Engine
V8 has...
Pointer to class data member “::*”
...ed in pluggable architectures, but once again producing an example in a small space defeats me. The following is my best (untested) try - an Apply function that would do some pre &post processing before applying a user-selected member function to an object:
void Apply( SomeClass * c, void (Som...
UnicodeDecodeError when redirecting to file
...n byte chunks. The necessary process that converts characters to bytes is called encoding. Thus, a computer requires an encoding in order to represent characters. Any text present on your computer is encoded (until it is displayed), whether it be sent to a terminal (which expects characters encode...
How to not run an example using roxygen2?
...answer instead of dontrun. From ?example 'donttest encloses code that typically should be run, but not during package checking.' whereas 'dontrun encloses code that should not be run.' I also got a comment by cran maintainers to switch from dontrun to donttest.
– Julian Karch
...
Android update activity UI from service
I have a service which is checking for new task all the time. If there is new task, I want to refresh the activity UI to show that info.
I did find https://github.com/commonsguy/cw-andtutorials/tree/master/18-LocalService/ this example. Is that a good approch ? Any other examples?
...
in iPhone App How to detect the screen resolution of the device
...l give you the entire screen's resolution in points, so it would most typically be 320x480 for iPhones. Even though the iPhone4 has a much larger screen size iOS still gives back 320x480 instead of 640x960. This is mostly because of older applications breaking.
CGFloat screenScale = [[UIScreen main...