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How to filter None's out of List[Option]?
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someList.filter(_.isDefined) if you want to keep the result type as List[Option[A]]
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Can I change multiplier property for NSLayoutConstraint?
...them, since "Activating or deactivating the constraint calls addConstraint(_:) and removeConstraint(_:) on the view that is the closest common ancestor of the items managed by this constraint".
– qix
Jan 4 '17 at 5:26
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What is Hindley-Milner?
...er system is that each well-typed term has a unique "best" type, which is called the principal type. The principal type of the list-length function is "for any a, function from list of a to integer". Here a is a so-called "type parameter," which is explicit in lambda calculus but implicit in most ...
What is a “context bound” in Scala?
... Iterable[T]) =
xs zip ys map { t => implicitly[Numeric[T]].times(t._1, t._2) }
or
def **[T : Numeric](xs: Iterable[T], ys: Iterable[T]) =
xs zip ys map { t => context[T]().times(t._1, t._2) }
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How to remove files that are listed in the .gitignore but still on the repository?
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You can remove them from the repository manually:
git rm --cached file1 file2 dir/file3
Or, if you have a lot of files:
git rm --cached `git ls-files -i --exclude-from=.gitignore`
But this doesn't seem to work in Git Bash on Windows. It produces an error messag...
How to sort mongodb with pymongo
...rameters.
So if you want to sort by, let's say, id then you should .sort("_id", 1)
For multiple fields:
.sort([("field1", pymongo.ASCENDING), ("field2", pymongo.DESCENDING)])
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Running multiple commands with xargs
...gs -d $'\n' sh -c 'for arg do command1 "$arg"; command2 "$arg"; ...; done' _
...or, without a Useless Use Of cat:
<a.txt xargs -d $'\n' sh -c 'for arg do command1 "$arg"; command2 "$arg"; ...; done' _
To explain some of the finer points:
The use of "$arg" instead of % (and the absence of...
Moving average or running mean
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UPD: more efficient solutions have been proposed by Alleo and jasaarim.
You can use np.convolve for that:
np.convolve(x, np.ones((N,))/N, mode='valid')
Explanation
The running mean is a case of the mathematical operation of convolution. For the running mean, you slide...
MySQL “NOT IN” query
I wanted to run a simple query to throw up all the rows of Table1 where a principal column value is not present in a column in another table ( Table2 ).
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How to “inverse match” with regex?
...place of .{6}
Edit (again): Note that lookaheads and lookbehinds are generally not the right way to "inverse" a regular expression match. Regexps aren't really set up for doing negative matching, they leave that to whatever language you are using them with.
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