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dplyr summarise: Equivalent of “.drop=FALSE” to keep groups with zero length in output
When using summarise with plyr 's ddply function, empty categories are dropped by default. You can change this behavior by adding .drop = FALSE . However, this doesn't work when using summarise with dplyr . Is there another way to keep empty categories in the result?
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Detecting arrow key presses in JavaScript
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Some browsers do trigger keypress events for arrow keys, but you're right that keydown always works for arrow keys.
– Tim Down
Apr 8 '11 at 15:37
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What is the difference between ndarray and array in numpy?
...ng of numpy.ndarray:
Arrays should be constructed using array, zeros or empty ... The parameters given here refer to a
low-level method (ndarray(...)) for instantiating an array.
Most of the meat of the implementation is in C code, here in multiarray, but you can start looking at the ndar...
What is memory fragmentation?
I've heard the term "memory fragmentation" used a few times in the context of C++ dynamic memory allocation. I've found some questions about how to deal with memory fragmentation, but can't find a direct question that deals with it itself. So:
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Calling startActivity() from outside of an Activity context
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Either
cache the Context object via constructor in your adapter, or
get it from your view.
Or as a last resort,
add - FLAG_ACTIVITY_NEW_TASK flag to your intent:
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myIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
Edit - i would avoid setting flags as it will ...
IDEA: javac: source release 1.7 requires target release 1.7
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Most likely you have incorrect compiler options imported from Maven here:
Also check project and module bytecode (target) version settings outlined on the screenshot.
Other places where the source language level is configured:
Project Structur...
static function in C
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Is translation unit the correct terminology to use here? Wouldn't object file be more accurate? From what I understand, a static function is hidden from the linker and the linker does not operate on translation units.
– Steven E...
Difference between Pragma and Cache-Control headers?
...to prevent the client from caching the response. Older clients may not support HTTP/1.1 which is why that header is still in use.
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In Objective-C, how do I test the object type?
I need to test whether the object is of type NSString or UIImageView . How can I accomplish this? Is there some type of "isoftype" method?
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How can I print variable and string on same line in Python?
I am using python to work out how many children would be born in 5 years if a child was born every 7 seconds. The problem is on my last line. How do I get a variable to work when I'm printing text either side of it?
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