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Fastest way to replace NAs in a large data.table
... data.table , with many missing values scattered throughout its ~200k rows and 200 columns. I would like to re code those NA values to zeros as efficiently as possible.
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When should null values of Boolean be used?
Java boolean allows values of true and false while Boolean allows true , false , and null . I have started to convert my boolean s to Boolean s. This can cause crashes in tests such as
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pip installing in global site-packages instead of virtualenv
...r instead of the one in the virtualenv folder. Here's how I set up Python3 and virtualenv on OS X Mavericks (10.9.1):
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Where can I find php.ini?
A few years ago I installed Apache 2.2x and PHP 5.3.1 on a Linux server I maintain. I used .tar.gz's and built them as instructed (instead of rpms and what-have-you). And all was fine.
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Difference between malloc and calloc?
...tage of the OS's guarantee.
This means calloc memory can still be "clean" and lazily-allocated, and copy-on-write mapped to a system-wide shared physical page of zeros. (Assuming a system with virtual memory.)
Some compilers even can optimize malloc + memset(0) into calloc for you, but you should...
Is it bad to have my virtualenv directory inside my git repository?
... repository for the app. It seems like an easy way to keep deploy's simple and easy. Is there any reason why I shouldn't do this?
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Can enums be subclassed to add new elements?
I want to take an existing enum and add more elements to it as follows:
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What is the difference between 'E', 'T', and '?' for Java generics?
...the Java programming language
Angelika Langer's Java Generics FAQ (massive and comprehensive; more for reference though)
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How to manage a redirect request after a jQuery Ajax call
I'm using $.post() to call a servlet using Ajax and then using the resulting HTML fragment to replace a div element in the user's current page. However, if the session times out, the server sends a redirect directive to send the user to the login page. In this case, jQuery is replacing the div ...
invalid context 0x0 under iOS 7.0 and system degradation
...oubt that's the issue. These invalid context 0x0 error messages are common and easy to reproduce in iOS 7. In fact, I can reproduce the error using storyboard with zero code. I drag a UITextField onto the canvas in IB, run the app, and double tap inside the text field.
In many situations, it's har...