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How to check 'undefined' value in jQuery
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JQuery library was developed specifically to simplify and to unify certain JavaScript functionality.
However if you need to check a variable against undefined value, there is no need to invent any special method, since JavaScript has a typeof operator, which is...
Get top n records for each group of grouped results
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Here is one way to do this, using UNION ALL (See SQL Fiddle with Demo). This works with two groups, if you have more than two groups, then you would need to specify the group number and add queries for each group:
(
select *
from mytable
where `group` = 1
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How to define optional methods in Swift protocol?
...an take advantage of powerful generics system.
You can always be sure that all requirements are met when encountering types that conform to such protocol. It's always either concrete implementation or default one. This is how "interfaces" or "contracts" behave in other languages.
Disadvantages
F...
Good or bad practice for Dialogs in wpf with MVVM?
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What if instead of using services, one uses a sort of Callback to facilitate interaction with the ViewModel and the View? For example, View executes a Command in the ViewModel, then when all is said and done, the ViewModel fires a Callback for the View to display the results of t...
How to determine CPU and memory consumption from inside a process?
... quite a while, perhaps I've been only a bit stupid...)
Note: for clarity all error checking has been omitted from the following code. Do check the return codes...!
Total Virtual Memory:
#include "windows.h"
MEMORYSTATUSEX memInfo;
memInfo.dwLength = sizeof(MEMORYSTATUSEX);
GlobalMemoryStatus...
Python non-greedy regexes
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You seek the all-powerful *?
From the docs, Greedy versus Non-Greedy
the non-greedy qualifiers *?, +?, ??, or {m,n}? [...] match as little
text as possible.
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Best Practice: Initialize JUnit class fields in setUp() or at declaration?
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If you're wondering specifically about the examples in the JUnit FAQ, such as the basic test template, I think the best practice being shown off there is that the class under test should be instantiated in your setUp method (or in a test method).
When ...
Interface or an Abstract Class: which one to use?
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I was trying all day to understand the usages of abstract and interface classes, your post made it all clear. Thanks a lot Alan
– afarazit
May 21 '11 at 12:51
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How to handle floats and decimal separators with html5 input type number
... has a default value of 1. If you want the input's validation algorithm to allow floating-point values, specify a step accordingly.
For example, I wanted dollar amounts, so I specified a step like this:
<input type="number" name="price"
pattern="[0-9]+([\.,][0-9]+)?" step="0.01"
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How to completely remove a dialog on close
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If you are using a div from the DOM, so not dynamically created, use .empty(). Then you can reuse it, if you fill the contents again offcourse.
– KoalaBear
Jul 15 '13 at 21:14
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