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Storing time-series data, relational or non?
... description, the actual PK is (Device, Metric, DateTime). (Please don't call it TimeStamp, that means something else, but that is a minor issue.) The uniqueness of the row is identified by:
(Device, Metric, DateTime)
The Id column does nothing, it is totally and completely redundant.
A...
How can I use Timer (formerly NSTimer) in Swift?
...syntax (iOS 10+)
let timer = Timer(timeInterval: 0.4, repeats: true) { _ in print("Done!") }
// Swift >=3 selector syntax
let timer = Timer.scheduledTimer(timeInterval: 0.4, target: self, selector: #selector(self.update), userInfo: nil, repeats: true)
// Swift 2.2 selector syntax
...
Testing two JSON objects for equality ignoring child order in Java
...ary that supports comparing two JSON objects ignoring child order, specifically for unit testing JSON returning from a web service.
...
为iFrame添加动态载入效果，提高用户体验 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...ng="no"></iframe>
<script language="javascript">
function stateChangeIE(_frame)
{
if (_frame.readyState=="interactive")
{
var loader = document.getElementById("loading");
loader.innerHTML = "";
loader.style.display = "none";
_fra...
Difference between variable declaration syntaxes in Javascript (including global variables)?
...here are a couple of differences, though in practical terms they're not usually big ones.
There's a fourth way, and as of ES2015 (ES6) there's two more. I've added the fourth way at the end, but inserted the ES2015 ways after #1 (you'll see why), so we have:
var a = 0; // 1
let a = 0; // 1...
postgresql - replace all instances of a string within text field
In postgresql, how do I replace all instances of a string within a database column?
4 Answers
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Better way to sum a property value in an array
...
Updated Answer
Due to all the downsides of adding a function to the Array prototype, I am updating this answer to provide an alternative that keeps the syntax similar to the syntax originally requested in the question.
class TravellerCollection e...
Check if two unordered lists are equal [duplicate]
...has a built-in datatype for an unordered collection of (hashable) things, called a set. If you convert both lists to sets, the comparison will be unordered.
set(x) == set(y)
Documentation on set
EDIT: @mdwhatcott points out that you want to check for duplicates. set ignores these, so you need ...
Android Studio installation on Windows 7 fails, no JDK found
...
Adding a system variable JDK_HOME with value c:\Program Files\Java\jdk1.7.0_21\ worked for me. The latest Java release can be downloaded here.
Additionally, make sure the variable JAVA_HOME is also set with the above location.
...
Why is a round-trip conversion via a string not safe for a double?
...ber(value, 17, &number);
DoubleToNumber is pretty simple -- it just calls _ecvt, which is in the C runtime:
void DoubleToNumber(double value, int precision, NUMBER* number)
{
WRAPPER_CONTRACT
_ASSERTE(number != NULL);
number->precision = precision;
if (((FPDOUBLE*)&val...