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Linq: What is the difference between Select and Where

...rable<A> in, IEnumerable<A> out Select returns something for all items in the source (projection / transformation). That something might be the items themselves, but are more usually a projection of some sort. -> IEnumerable<A> in, IEnumerable<B> out ...
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Is there a way to detect if a browser window is not currently active?

I have JavaScript that is doing activity periodically. When the user is not looking at the site (i.e., the window or tab does not have focus), it'd be nice to not run. ...
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Why do Lua arrays(tables) start at 1 instead of 0?

... to love 0-based arrays. But I get by OK with Lua's 1-based arrays, especially by using Lua's generic for loop and the ipairs operator—I can usually avoid worrying about just how arrays are indexed. share | ...
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Long vs Integer, long vs int, what to use and when?

... inherited from Object, such as hashcode. Java.util.collections methods usually use the boxed (Object-wrapped) versions, because they need to work for any Object, and a primitive type, like int or long, is not an Object. Another difference is that long and int are pass-by-value, whereas Long and In...
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How to get the body's content of an iframe in Javascript?

...t try contentWindow.document. Select elements in iframe Then you can usually use getElementById() or even querySelectorAll() to select the DOM-Element from the iframeDocument: if (!iframeDocument) { throw "iframe couldn't be found in DOM."; } var iframeContent = iframeDocument.getElementByI...
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How to find out client ID of component for ajax update/render? Cannot find component with expression

..., <h:dataTable>, <p:tabView>, <cc:implementation> (thus, all composite components), etc. You recognize them easily by looking at the generated HTML output, their ID will be prepended to the generated client ID of all child components. Note that when they don't have a fixed ID, then...
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How to align checkboxes and their labels consistently cross-browsers

...lems that plagues me constantly. How do folks around Stack Overflow vertically align checkboxes and their labels consistently cross-browser ? Whenever I align them correctly in Safari (usually using vertical-align: baseline on the input ), they're completely off in Firefox and IE. Fix it ...
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How to use NULL or empty string in SQL

...pty string. REASON: if there is ONLY whitespace, a single trim will remove all of it. For example, you don't care whether the comparison fails because what remains is "abc" or " abc". – ToolmakerSteve Dec 9 '16 at 20:06 ...
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How can I tell Rails to use RSpec instead of test-unit when creating a new Rails app?

I have test-unit installed and rspec installed (along with -core , -expectations , -mocks and -rails version 2.6.x). When I run the command rails new foo , it uses test-unit to generate the test stub files instead of rspec . ...
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How to vertically align into the center of the content of a div with defined width/height?

What would be the correct method to vertically center any content in a defined width/height div . 4 Answers ...