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Group by multiple columns in dplyr, using string vector input

... (documentation here). This lets you use the same functions you would use with select, like so: data = data.frame( asihckhdoydkhxiydfgfTgdsx = sample(LETTERS[1:3], 100, replace=TRUE), a30mvxigxkghc5cdsvxvyv0ja = sample(LETTERS[1:3], 100, replace=TRUE), value = rnorm(100) ) # get the co...
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Can I use git diff on untracked files?

Is it possible to ask git diff to include untracked files in its diff output, or is my best bet to use git add on the newly created files and the existing files I have edited, then use: ...
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How to get all subsets of a set? (powerset)

... The Python itertools page has exactly a powerset recipe for this: from itertools import chain, combinations def powerset(iterable): "powerset([1,2,3]) --> () (1,) (2,) (3,) (1,2) (1,3) (2,3) (1,2,3)" s = list(iterable) ...
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jquery-ui sortable | How to get it work on iPad/touchdevices?

... Found a solution (only tested with iPad until now!)! http://touchpunch.furf.com/content.php?/sortable/default-functionality share | improve this answer ...
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Writing Unicode text to a text file?

I'm pulling data out of a Google doc, processing it, and writing it to a file (that eventually I will paste into a Wordpress page). ...
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What does static_assert do, and what would you use it for?

...t; 2, "Old versions of SomeLibrary are missing the foo functionality. Cannot proceed!"); class UsingSomeLibrary { // ... }; Assuming that SomeLibrary::Version is declared as a static const, rather than being #defined (as one would expect in a C++ library). Contrast with having to a...
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What are the differences between -std=c++11 and -std=gnu++11?

... -std=gnu++11 as compilation parameter for gcc and clang? Same question with c99 and gnu99 ? I know about C++ and C standards, it's the differences in the parameters that interest me. ...
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How to display all methods of an object?

...ined by the browser and most likely enumerable by design. From ECMA-262 Edition 3: Global Object There is a unique global object (15.1), which is created before control enters any execution context. Initially the global object has the following properties: • Built-in object...
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How to migrate back from initial migration in Django 1.7?

I created a new app with some models and now I noticed that some of the models are poorly thought out. As I haven't committed the code the sensible thing would be to migrate the database to last good state and redo the migration with better models. In this case the last good state is database where ...
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Example of multipart/form-data

I am wondering if anyone can share with me an example of multipart/form-data that contains: 2 Answers ...