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Why em instead of px?

I heard you should define sizes and distances in your stylesheet with em instead of in pixels. So the question is why should I use em instead of px when defining styles in css? Is there a good example that illustrates this? ...
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Reasons for using the set.seed function

...ion in R, before starting the program. I know it's basically used for the random number generation. Is there any specific need to set this? ...
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Why use pointers? [closed]

...tionality, missing data types or for pure perfomance. More below... When and where should I use pointers? Short answer here is: Where you cannot use anything else. In C you don't have any support for complex datatypes such as a string. There are also no way of passing a variable "by reference" ...
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Printing hexadecimal characters in C

... case), your chars are being promoted to int via sign-extension. Since c0 and 80 have a leading 1-bit (and are negative as an 8-bit integer), they are being sign-extended while the others in your sample don't. char int c0 -> ffffffc0 80 -> ffffff80 61 -> 00000061 Here's a solution: ...
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In Rails, how do you render JSON using a view?

Suppose you're in your users controller and you want to get a json response for a show request, it'd be nice if you could create a file in your views/users/ dir, named show.json and after your users#show action is completed, it renders the file. ...
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Multiple simultaneous downloads using Wget?

... Don't forget -s to specify the number of splits, and -k to specify the minimum size per split segment - otherwise you might never reach the -x max connections. – Bob Mar 11 '14 at 13:16 ...
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How to run Rake tasks from within Rake tasks?

...y_invoked state, allowing the task to then be executed again, dependencies and all: Rake::Task["build"].reenable Rake::Task["build"].invoke Note that dependencies already invoked are not automatically re-executed unless they are re-enabled. In Rake >= 10.3.2, you can use the following to re-ena...
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How to loop through all the properties of a class?

...scriptor; the good news is that this still works fine for regular classes (and can even be much quicker than reflection): foreach(PropertyDescriptor prop in TypeDescriptor.GetProperties(obj)) { Console.WriteLine("{0} = {1}", prop.Name, prop.GetValue(obj)); } This also provides easy access to ...
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pandas DataFrame: replace nan values with average of columns

I've got a pandas DataFrame filled mostly with real numbers, but there is a few nan values in it as well. 10 Answers ...
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jQuery scroll to element

...de from the article Smoothly scroll to an element without a jQuery plugin. And I have tested it on the example below. <html> <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.5.1/jquery.min.js"></script> <script> $(document).ready(function ()...