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dplyr summarise: Equivalent of “.drop=FALSE” to keep groups with zero length in output
...e to go with @Moody_Mudskipper's answer: Using .drop=FALSE can give potentially unexpected results when one or more grouping variables are not coded as factors. See examples below:
library(dplyr)
data(iris)
# Add an additional level to Species
iris$Species = factor(iris$Species, levels=c(levels(ir...
Set scroll position
...'m trying to set the scroll position on a page so the scroller is scrolled all the way to the top.
4 Answers
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All permutations of a Windows license key
... it gave the answers in a very clean way for copy and paste. There was actually a 5th variable, and I got my key!! I actually gave the "write it down" task to a colleague, and he gave up! Thanks a lot.
– Kerridge0
Jan 31 '13 at 15:50
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What's the difference between --general-numeric-sort and --numeric-sort options in gnu sort
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General numeric sort compares the numbers as floats, this allows scientific notation eg 1.234E10 but is slower and subject to rounding error (1.2345678 could come after 1.2345679), numeric sort is just a regular alphabetic sort that knows 10 comes after 9.
See http://www.gnu.o...
What is the difference between isinstance('aaa', basestring) and isinstance('aaa', str)?
...trings, would it not be better to just have Unicode since that would cover all the cases? Well it is better to have only Unicode but Python was created before Unicode was the preferred method for representing strings. It takes time to transition the string type in a language with many users, in Pyth...
What are the complexity guarantees of the standard containers?
...found the nice resource Standard C++ Containers. Probably this is what you all looking for.
VECTOR
Constructors
vector<T> v; Make an empty vector. O(1)
vector<T> v(n); Make a vector with N elements. ...
How to Copy Contents of One Canvas to Another Canvas Locally
I'd like to copy ALL contents of one canvas and transfer them to another all on the client-side. I would think that I would use the canvas.toDataURL() and context.drawImage() method to implement this but I am running into a few issues.
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What does addChildViewController actually do?
...s I've had to do is implement a custom container view controller - lets call it SideBarViewController - that swaps out which of several possible child view controllers it shows, almost exactly like a standard Tab Bar Controller . (It's pretty much a Tab Bar Controller but with a hideable side...
Why is whitespace sometimes needed around metacharacters?
...s a list of characters that separate tokens in BASH. These characters are called metacharacters and they are |, &, ;, (, ), <, >, space and tab. On the other hand, curly braces ({ and }) are just ordinary characters that make up words.
Omitting the second space before } will do, since &am...
Difference between a Postback and a Callback
I keep on hearing this words ' callback ' and ' postback ' tossed around.
What is the difference between two ?
6 Answers...