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What does = +_ mean in JavaScript
...page on Arithmetic Operators:
The unary plus operator precedes its operand and evaluates to its
operand but attempts to converts it into a number, if it isn't
already. [...] It can convert string representations of integers and
floats, as well as the non-string values true, false, and null...
Difference between CMAKE_CURRENT_SOURCE_DIR and CMAKE_CURRENT_LIST_DIR
...
The variables CMAKE_CURRENT_SOURCE_DIR and CMAKE_CURRENT_LIST_DIR may refer to different directories for a CMake list file that is included by another file with the include command. E.g., if a CMakeLists.txt is present in a directory project and contains the foll...
Vim indent xml file
...want to format.
Then, in normal mode, type ! xmllint --format -
Your command-line at the bottom will look like this:
:'<,'>!xmllint --format -
Then hit enter.
Technical Explanation
The selected text is sent to the xmllint command, then --format'ed, and the results of xmllint are placed o...
How to make a chain of function decorators?
...dule from PyPI: they preserve certain important metadata (such as __name__ and, speaking about the decorator package, function signature).
– Marius Gedminas
Mar 11 '11 at 2:30
...
Drop data frame columns by name
...DF) %in% drops)]
Or, alternatively, you can make a list of those to keep and refer to them by name :
keeps <- c("y", "a")
DF[keeps]
EDIT :
For those still not acquainted with the drop argument of the indexing function, if you want to keep one column as a data frame, you do:
keeps <- "y"
...
What does the Ellipsis object do?
...nterpretation is purely up to whatever implements the __getitem__ function and sees Ellipsis objects there, but its main (and intended) use is in the numpy third-party library, which adds a multidimensional array type. Since there are more than one dimensions, slicing becomes more complex than just...
How to create multidimensional array
...2[0] == 'input3';
mixed.row2[1] == 'input4';
http://jsfiddle.net/z4Un3/
And if you're wanting to store DOM elements:
var inputs = [
[
document.createElement('input'),
document.createElement('input')
],
[
document.createElement('input'),
document.create...
Does async(launch::async) in C++11 make thread pools obsolete for avoiding expensive thread creation
...rong. I was under the impression that Linux thread creation was very cheap and after testing I determined that the overhead of function call in a new thread vs. a normal one is enormous. The overhead for creating a thread to handle a function call is something like 10000 or more times slower than a ...
Should I use 'has_key()' or 'in' on Python dicts?
...ng, I didn't see that. I suppose it's because x in d.keys() must construct and destroy a temporary object, complete with the memory allocation that entails, where x in d.keys() is just doing an arithmetic operation (computing the hash) and doing a lookup. Note that d.keys() is only about 10 times as...
UTF-8: General? Bin? Unicode?
...pares as equal to combinations of other characters. For example, in German and some other languages “ß” is equal to “ss”. utf8_unicode_ci also supports contractions and ignorable characters. utf8_general_ci is a legacy collation that does not support expansions, contractions, or ignorable ...