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Hidden features of Scala
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Case classes automatically mixin the Product trait, providing untyped, indexed access to the fields without any reflection:
case class Person(name: String, age: Int)
val p = Person("Aaron", 28)
val name = p.productElement(0) // name = "Aaron": Any
val age = p.productElement(1) // age = 28: Any...
Measure elapsed time in Swift
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let start = NSDate()
for index in 1...10000 {
// do nothing
}
let elapsed = start.timeIntervalSinceNow
// elapsed is a negative value.
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Why doesn't Java support unsigned ints?
...t be negative, then it also needs subranges (a la Pascal) because an array index can't be greater than the array size.
– Wayne Conrad
Jan 27 '10 at 5:05
84
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How to delete a row by reference in data.table?
.... 'keep.idxs'
keep.idxs <- setdiff(DT[, .I], del.idxs); # select row indexes to keep
cols = names(DT);
DT.subset <- data.table(DT[[1]][keep.idxs]); # this is the subsetted table
setnames(DT.subset, cols[1]);
for (col in cols[2:length(cols)]) {
DT.subset[, (col) := DT[[col]][keep...
Rails 4: before_filter vs. before_action
...ifference, in rails app there is CRUD, and seven actions basically by name index, new, create, show, update, edit, destroy.
Rails 4 make it developer friendly to change syntax before filter to before action.
before_action call method before the actions which we declare, like
before_action :set_ev...
Pair/tuple data type in Go
...g interface{}. (I might have used an array rather than a struct to make it indexable like a tuple, but the key idea is the interface{} type)
My other answer shows how you can do something similar that avoids creating a type using anonymous structs.
These techniques have some properties of tuples, ...
Using .otf fonts on web browsers
...ttp://www.alistapart.com/articles/cssatten
Other Info:
http://randsco.com/index.php/2009/07/04/p680
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How to check whether an array is empty using PHP?
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old school da best as always, just check the index of array.
– Danish
Feb 12 '18 at 8:33
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How can I alter a primary key constraint using SQL syntax?
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Performance wise there is no point to keep non clustered indexes during this as they will get re-updated on drop and create.
If it is a big data set you should consider renaming the table (if possible , any security settings on it?), re-creating an empty table with the correct keys...
How do you run NUnit tests from Jenkins?
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endlocal
exit %ERRORLEVEL%
Reference: http://www.greengingerwine.com/index.php/2013/01/tip-check-errorlevel-in-your-post-build-steps-when-using-nunit/
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