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Constructors vs Factory Methods [closed]

...ns: Elements of Reusable Object-Oriented Software by Gamma, Helm, Johnson, and Vlissides. Use the Factory Method pattern when a class can't anticipate the class of objects it must create a class wants its subclasses to specify the objects it creates classes delegate responsibility to one of sever...
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Replace console output in Python

... An easy solution is just writing "\r" before the string and not adding a newline; if the string never gets shorter this is sufficient... sys.stdout.write("\rDoing thing %i" % i) sys.stdout.flush() Slightly more sophisticated is a progress bar... this is something I am using: d...
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How to check for an undefined or null variable in JavaScript?

...xistingObj.someUndefProperty. An undefined property doesn't yield an error and simply returns undefined, which, when converted to a boolean, evaluates to false. So, if you don't care about 0 and false, using if(obj.undefProp) is ok. There's a common idiom based on this fact: value = obj.prop || de...
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What is the difference between old style and new style classes in Python?

What is the difference between old style and new style classes in Python? When should I use one or the other? 8 Answers ...
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Maintain the aspect ratio of a div with CSS

...rce: w3.org, emphasis mine) Padding-bottom values for other aspect ratios and 100% width : aspect ratio | padding-bottom value --------------|---------------------- 16:9 | 56.25% 4:3 | 75% 3:2 | 66.66% 8:5 | 62.5% Placing content in ...
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How do you performance test JavaScript code?

...e user/client. For example, we had a project with an Ext accordion that expanded to show some data and then a few nested Ext grids. Everything was actually rendering pretty fast, no single operation took a long time, there was just a lot of information being rendered all at once, so it felt slow to...
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Why doesn't the height of a container element increase if it contains floated elements?

I would like to ask how height and float work. I have an outer div and an inner div that has content in it. Its height may vary depending on the content of the inner div but it seems that my inner div will overflow its outside div. What would be the proper way to do it? ...
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Android: How to stretch an image to the screen width while maintaining aspect ratio?

...to download an image (of unknown size, but which is always roughly square) and display it so that it fills the screen horizontally, and stretches vertically to maintain the aspect ratio of the image, on any screen size. Here is my (non-working) code. It stretches the image horizontally, but not vert...
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Does using “new” on a struct allocate it on the heap or stack?

...ut where value type variables are allocated. That's a different question - and one to which the answer isn't just "on the stack". It's more complicated than that (and made even more complicated by C# 2). I have an article on the topic and will expand on it if requested, but let's deal with just the ...
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Encode URL in JavaScript?

... Check out the built-in function encodeURIComponent(str) and encodeURI(str). In your case, this should work: var myOtherUrl = "http://example.com/index.html?url=" + encodeURIComponent(myUrl); shar...