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How to parse XML to R data frame
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Data in XML format are rarely organized in a way that would allow the xmlToDataFrame function to work. You're better off extracting everything in lists and then binding the lists together in a data frame:
require(XML)
data <- xmlParse("http://forecast.weather.gov/MapClick.php?lat=...
Is it a good idea to index datetime field in mysql?
...atabase is very broad. I'd say to just make sure that it's normalized and all appropriate columns are indexed (i.e. ones used in joins and where clauses).
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How efficient is locking an unlocked mutex? What is the cost of a mutex?
... access to the object happens often, then multiple locks would increase parallelism. At the cost of maintainability, since more locking means more debugging of the locking.
How efficient is it to lock a mutex? I.e. how much assembler instructions are there likely and how much time do they take (...
ASP.NET MVC JsonResult Date Format
...answer.
The JSON spec does not account for Date values. MS had to make a call, and the path they chose was to exploit a little trick in the javascript representation of strings: the string literal "/" is the same as "\/", and a string literal will never get serialized to "\/" (even "\/" must be map...
Is C++ context-free or context-sensitive?
... is (probably) Turing-complete, since it shows a program which is syntactically correct if and only if a given integer is prime.
So I assert that C++ is neither context-free nor context-sensitive.
If you allow arbitrary symbol sequences on both sides of any production, you produce an Type-0 gramma...
Compiling simple Hello World program on OS X via command line
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@mathepic: That's 1 opinion. Personally I find it clearer to not to use it.
– Martin York
Nov 2 '10 at 3:31
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Python Remove last 3 characters of a string
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Removing any and all whitespace:
foo = ''.join(foo.split())
Removing last three characters:
foo = foo[:-3]
Converting to capital letters:
foo = foo.upper()
All of that code in one line:
foo = ''.join(foo.split())[:-3].upper()
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Getting the error “Missing $ inserted” in LaTeX
...ommand, which will typeset the text in a monospaced font and will automatically handle underscores and bars correctly (no need to escape them with \).
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How to generate a random alpha-numeric string?
...er that would "likely" be unique over 500K+ generation (my needs don't really require anything much more sophisticated).
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JSON Naming Convention (snake_case, camelCase or PascalCase) [closed]
Is there a standard on JSON naming? I see most examples using all lower case separated by underscore, aka snake_case , but can it be used PascalCase or camelCase as well?
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