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How to delete multiple values from a vector?
...LSE FALSE
> a [! a %in% remove]
[1] 10 7 1 6 4 8 9
Note that this will silently remove incomparables (stuff like NA or Inf) as well (while it will keep duplicate values in a as long as they are not listed in remove).
If a can contain incomparables, but remove will not, we can use matc...
What's wrong with foreign keys?
...lps the Optimizer plan your queries for most efficient execution, since it is able to get better estimates on join cardinality.
FKs give a pretty big hint on what statistics are most important to collect on the database, which in turn leads to better performance
they enable all kinds of auto-genera...
parseInt vs unary plus, when to use which?
What are the differences between this line:
5 Answers
5
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Matplotlib discrete colorbar
I am trying to make a discrete colorbar for a scatterplot in matplotlib
7 Answers
7
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What is the apply function in Scala?
...tion f to its argument x".
In mathematics and computer science, Apply is a function that applies
functions to arguments.
Wikipedia
apply serves the purpose of closing the gap between Object-Oriented and Functional paradigms in Scala. Every function in Scala can be represented as an objec...
sed edit file in place
I am trying to find out if it is possible to edit a file in a single sed command without manually streaming the edited content into a new file and then renaming the new file to the original file name. I tried the -i option but my Solaris system said that -i is an illegal option. Is there a d...
What is ActiveMQ used for - can we apply messaging concept using a Database?
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It is used to reliably communicate between two distributed processes.
Yes, you could store messages in a Database to communicate between two processes, but, as soon as the message is received you'd have to DELETE the message,...
What is the optimal Jewish toenail cutting algorithm?
...ith no restrictions, and then filter out all sequences that violate the jewish rule. Luckily, humans only have five toes per foot*, so there are only 5! = 120 unrestricted sequences.
Python example:
#seq is only valid when consecutive elements in the list differ by at least two.
def isValid(seq):...
What do the makefile symbols $@ and $< mean?
...
$@ is the name of the target being generated, and $< the first prerequisite (usually a source file). You can find a list of all these special variables in the GNU Make manual.
For example, consider the following declaration:
...
What's the difference between `on` and `live` or `bind`?
...
on() is an attempt to merge most of jQuery's event binding functions into one. This has the added bonus of tidying up the inefficiencies with live vs delegate. In future versions of jQuery, these methods will be removed and only...