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How to reorder data.table columns (without copying)
... 2 2
# [3,] 0.3297416 1 3
From ?setcolorder:
In data.table parlance, all set* functions change their input by reference. That is, no copy is made at all, other than temporary working memory, which is as large as one column.
so should be pretty efficient. See ?setcolorder for details.
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Safe String to BigDecimal conversion
...0,000,000.999999999999999";
BigDecimal money = new BigDecimal(value.replaceAll(",", ""));
System.out.println(money);
Full code to prove that no NumberFormatException is thrown:
import java.math.BigDecimal;
public class Tester {
public static void main(String[] args) {
// TODO Auto-...
Create the perfect JPA entity [closed]
...nd your time on what's important.
Constructors: create a constructor with all required fields of the entity?
Constructor(s) for application logic, should have only a few critical "foreign key" or "type/kind" fields which will always be known when creating the entity. The rest should be set by call...
Why NSUserDefaults failed to save NSMutableDictionary in iOS?
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When do I need to release the loaded object? No alloc was called, so I would assume it is autorelased?
– Marc
Apr 16 '12 at 13:08
7
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Good reasons NOT to use a relational database?
...l system)
Very good support for versioning of data
Berkeley DB (Basically, a disk based hashtable)
Very simple conceptually (just un-typed key/value)
Quite fast
No administration overhead
Supports transactions I believe
Amazon's Simple DB
Much like Berkeley DB I believe, but hosted
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Easy way of running the same junit test over and over?
...for some simple way to run JUnit 4.x tests several times in a row automatically using Eclipse.
12 Answers
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How to apply !important using .css()?
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small fix when style is empty: $('#elem').attr('style', function(i,s) { return (s||'') + 'width: 100px !important;' });
– falko
Oct 10 '13 at 8:47
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How to retrieve POST query parameters?
... Express 3.0.
This was different starting Express 4.0 to 4.15:
$ npm install --save body-parser
and then:
var bodyParser = require('body-parser')
app.use( bodyParser.json() ); // to support JSON-encoded bodies
app.use(bodyParser.urlencoded({ // to support URL-encoded bodies
extended...
What is the difference between properties and attributes in HTML?
...attribute. Instead, it's the current value of the input. When the user manually changes the value of the input box, the value property will reflect this change. So if the user inputs "John" into the input box, then:
theInput.value // returns "John"
whereas:
theInput.getAttribute('value') // retu...
How to insert an element after another element in JavaScript without using a library?
...or Ease of Use
By building the following prototypes, you will be able to call these function directly from newly created elements.
newElement.appendBefore(element);
newElement.appendAfter(element);
.appendBefore(element) Prototype
Element.prototype.appendBefore = function (element) {
eleme...