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What's the fastest way to merge/join data.frames in R?
...low we illustrate these points.
Its worthwhile to notice that the precise computation can make a huge difference on which package is fastest. For example, we do a merge and an aggregate below. We see that the results are nearly reversed for the two. In the first example from fastest to slowest w...
What is the difference between concurrency and parallelism?
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Concurrency is when two or more tasks can start, run, and complete in overlapping time periods. It doesn't necessarily mean they'll ever both be running at the same instant. For example, multitasking on a single-core machine.
Parallelism is when tasks literally run at the same ti...
Best way to concatenate List of String objects? [duplicate]
... You can be 99.9% certain that ArrayList.toString won't change unless it becomes an attack vector somehow; backward compatibility will see to that. But I agree that using toString() is still a bad idea.
– Barry Kelly
Oct 24 '13 at 9:00
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Boost Statechart vs. Meta State Machine
...rmation on the performance/scalability tradeoffs can be found here:
http://www.boost.org/doc/libs/1_45_0/libs/statechart/doc/performance.html
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When to use generic methods and when to use wild-card?
I am reading about generic methods from OracleDocGenericMethod . I am pretty confused about the comparison when it says when to use wild-card and when to use generic methods.
Quoting from the document.
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Using `textField:shouldChangeCharactersInRange:`, how do I get the text including the current typed
...te two characters. For me, the following suggestion worked: stackoverflow.com/questions/388237/… Basically, drag'n'drop from the UITextField into your code (to create a function), then right-click on your TextField, and drag'n'drop from the circle for the "Editing Changed" to your new function...
How to set a cookie for another domain
...ad user experience you can set an image on domain A.
<img src="http://www.example.com/cookie.php?val=123" style="display:none;">
And then on domain B that is example.com in cookie.php you'll have the following code:
<?php
setcookie('a', $_GET['val']);
?>
Hattip to Subin
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Converting Integer to Long
...the inheritance structure doesn't have any information that would tell the compiler that.
– MrMas
Mar 27 '13 at 13:50
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How to disable / enable dialog negative positive buttons?
Please look at the custom dialog below. I have an edittext field on the dialog and if the text field is empty I would like to disable the positiveButton . I can get a charListener for the text field but I am not sure how I am going to set the positivebutton to disable or enable from that listene...
How to create new tmux session if none exists
I am trying to figure out how to attach to a tmux session if a named tmux session exists, if not I want to create a new one with the given name.
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