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Why is `[` better than `subset`?
...vars, drop = drop]. The problem is how to get from the unquoted subset and select arguments to something that you can validly pass to [.data.frame.
– joran
Oct 2 '17 at 21:33
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Explicitly calling return in a function or not
...son for not using explicit return. The following plot is created from data selected this way:
bench_nor2 <- function(x,repeats) { system.time(rep(
# without explicit return
(function(x) vector(length=x,mode="numeric"))(x)
,repeats)) }
bench_ret2 <- function(x,repeats) { system.time(rep(
# wi...
How do cache lines work?
...(DDR1/2/3/4 SDRAM burst transfer size is configurable up to 64B; CPUs will select the burst transfer size to match their cache line size, but 64B is common)
As a rule of thumb, if the processor can't forecast a memory access (and prefetch it), the retrieval process can take ~90 nanoseconds, or ~250...
Whether a variable is undefined [duplicate]
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jQuery.val() and .text() will never return 'undefined' for an empty selection. It always returns an empty string (i.e. ""). .html() will return null if the element doesn't exist though.You need to do:
if(page_name != '')
For other variables that don't come from something like jQuery.val(...
Representing and solving a maze given an image
...otoshop in Image -> Adjustments -> Threshold.
Make sure threshold is selected right. Use the Magic Wand Tool with 0 tolerance, point sample, contiguous, no anti-aliasing. Check that edges at which selection breaks are not false edges introduced by wrong threshold. In fact, all interior points ...
Defining a HTML template to append using JQuery
...able to take the same approach using vanilla javascript with document.querySelector and .innerHTML.
jsfiddle
Templates inside JS
A question to ask yourself is: do you really want/need to define templates as HTML files? You can always componentize + re-use a template the same way you'd re-use most...
Get all inherited classes of an abstract class [duplicate]
...d This will search all assemblies: AppDomain.CurrentDomain.GetAssemblies().SelectMany(s => s.GetTypes()).Where(....
– Brain2000
Aug 24 '18 at 20:34
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Variables not showing while debugging in Eclipse
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try a right click on the variable and select inspect, then it should come up in a popup window
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UPDATE and REPLACE part of a string
... (N'19-4-2015', N'Monay', 2)
DECLARE @Date Nvarchar(200)
SET @Date = (SELECT [Date] FROM Tbl_PersonalDetail WHERE ID = 2)
Update Tbl_PersonalDetail SET [Date] = (REPLACE(@Date , '-','/')) WHERE ID = 2
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Regex - Should hyphens be escaped? [duplicate]
Hyphen is a special character in regex, for instance, to select a range, I could do something like:
3 Answers
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