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Grouping functions (tapply, by, aggregate) and the *apply family
...1:20
A factor (of the same length!) defining groups:
y <- factor(rep(letters[1:5], each = 4))
Add up the values in x within each subgroup defined by y:
tapply(x, y, sum)
a b c d e
10 26 42 58 74
More complex examples can be handled where the subgroups are defined
by the unique c...
How to detect if multiple keys are pressed at once using JavaScript?
...or myself in this example, the concept works just as well when working in 'raw' Javascript.
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What does “Could not find or load main class” mean?
...s from websites, documents and so on. And consider "homoglyphs", were two letters or symbols look the same ... but aren't.
Finally, you can apparently run into this problem if you try to launch from a JAR file with incorrect signatures in (META-INF/*.SF).
Alternative syntaxes for java
There ar...
Reduce, fold or scan (Left/Right)?
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@Marc, I like the examples with letters, it made things very clear
– Muhammad Farag
Jul 18 '15 at 21:13
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How to draw a path on a map using kml file?
... navigationDataSet = null;
}
return navigationDataSet;
}
}
Drawing:
/**
* Does the actual drawing of the route, based on the geo points provided in the nav set
*
* @param navSet Navigation set bean that holds the route information, incl. geo pos
* @param color Color in w...
C dynamically growing array
I have a program that reads a "raw" list of in-game entities, and I intend to make an array holding an index number (int) of an indeterminate number of entities, for processing various things. I would like to avoid using too much memory or CPU for keeping such indexes...
...
Should I use Vagrant or Docker for creating an isolated environment? [closed]
... a provider directly on the host or any VM (Mac, Win). It can also spin up raw LXC if thats what someone wants (again, on the host or VM). Vagrant is interested in doing what is best to create a portable development environment, whether that means creating a VM or not.
– Mitche...
How can I improve my paw detection?
...the data for each paw with [data[x] for x in data_slices]. Instead, we'll draw a rectangle based on these slices, which takes slightly more work.
The two animations below show your "Overlapping Paws" and "Grouped Paws" example data. This method seems to be working perfectly. (And for whatever i...
What's the difference between equal?, eql?, ===, and ==?
...ifferent order are not equal, uppercase and lowercase versions of the same letter are not equal and so on.
When comparing numbers of different types (e.g., integer and float), if their numeric value is the same, == will return true.
2 == 2.0 # Output: => true
equal?
Unlike the == operator w...
Expand a random range from 1–5 to 1–7
...e copies of each integer in the interval [1, 7], plus four zeroes. So the "raw" stream of results tends to an even mixture of [1, 7] values, plus some zeroes that occur a tad more frequently than any individual allowed value. But that doesn't matter because the zeros are stripped out, leaving just a...