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Why is rbindlist “better” than rbind?
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rbindlist is an optimized version of do.call(rbind, list(...)), which is known for being slow when using rbind.data.frame
Where does it really excel
Some questions that show where rbindlist shines are
Fast vectorized merge of list of data.frames by row
Trouble...
Print newline in PHP in single quotes
...pe sequence you can use in single quotes is for the single quote itself.
$foo = 'That\'s great';
The only way you could insert a new line into a string created with single quotes is to insert a literal newline
$bar = 'That\'s
cheating';
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Why historically do people use 255 not 256 for database field magnitudes?
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And reading into char foo[256] is important because memory management likes powers of 2. see: stackoverflow.com/questions/3190146/… Allocating char foo[257] will either fragment memory or take up 512 bytes.
– ebyrob
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Using getopts to process long and short command line options
...or using the bash builtin getopts to mimic long options. That solution actually makes a short option whose character is "-". So you get "--" as the flag. Then anything following that becomes OPTARG, and you test the OPTARG with a nested case.
This is clever, but it comes with caveats:
getopts ca...
Why am I merging “remote-tracking branch 'origin/develop' into develop”?
...iverged:
git rebase -p @{u}
Explanation
git remote update -p downloads all of the commits in the remote repositories and updates the remote tracking branches (e.g., origin/master). It does NOT touch your working directory, index, or local branches.
The -p argument prunes deleted upstream branc...
How to get request URI without context path?
...pring MVC. It will then represent the MVC framework's internal path (e.g. /foo.xhtml instead of /foo.jsf) and not the actual request URI (the one as enduser would see in browser's address bar). The original servlet path is in such case however resolveable as request attribute with key RequestDispatc...
Don't understand why UnboundLocalError occurs (closure) [duplicate]
...lError from a statement that uses an unbounded imported name. Example: def foo(): bar = deepcopy({'a':1}); from copy import deepcopy; return bar, then from copy import deepcopy; foo(). The call succeeds if the local import from copy import deepcopy is removed.
– Yibo Yang
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Why should C++ programmers minimize use of 'new'?
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There are two widely-used memory allocation techniques: automatic allocation and dynamic allocation. Commonly, there is a corresponding region of memory for each: the stack and the heap.
Stack
The stack always allocates memory in a sequential fashion. It c...
How do servlets work? Instantiation, sessions, shared variables and multithreading
... servlet container (like Apache Tomcat) starts up, it will deploy and load all its web applications. When a web application is loaded, the servlet container creates the ServletContext once and keeps it in the server's memory. The web app's web.xml and all of included web-fragment.xml files is parsed...
Passing an array to a function with variable number of args in Swift
... Great! This works with multiple (named) parameters, too; e.g.: func sumOf(foo numbers: Int..., bar: Bool) -> Int {}; requires typealias Function = (foo: [Int], bar: Bool) -> Int;
– ThomasR
Sep 11 '16 at 9:45
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