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What's the difference between getPath(), getAbsolutePath(), and getCanonicalPath() in Java?
....txt
C:\projects\sandbox\trunk\file.txt
So, getPath() gives you the path based on the File object, which may or may not be relative; getAbsolutePath() gives you an absolute path to the file; and getCanonicalPath() gives you the unique absolute path to the file. Notice that there are a huge number ...
How to use the 'sweep' function
...a weighted covariance matrix as per @James King's example.
Here's another based on a current project:
set.seed(1)
## 2x2x2 array
a1 <- array(as.integer(rnorm(8, 10, 5)), dim=c(2, 2, 2))
## 'element-wise' sum of matrices
## weights = 1
rowSums(a1, dims=2)
## weights
w1 <- c(3, 4)
## a1[, , 1]...
What is a race condition?
...rent.atomic, concurrent data structures, proper synchronization, and actor based concurrency will help.
The best resource for concurrency is JCIP. You can also get some more details on above explanation here.
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Java Enum definition
..., being able to say that Enum<E> implements Comparable<E>. The base class is able to do the comparisons (in the case of enums) but it can make sure that it only compares the right kind of enums with each other. (EDIT: Well, nearly - see the edit at the bottom.)
I've used something simil...
What's the fastest algorithm for sorting a linked list?
...
Comparison sorts (i.e. ones based on comparing elements) cannot possibly be faster than n log n. It doesn't matter what the underlying data structure is. See Wikipedia.
Other kinds of sort that take advantage of there being lots of identical elements i...
What is Linux’s native GUI API?
...int migrate to it, though there is still no clear schedule. This system is based on OpenGL/ES API, which means that in the future OpenGL will be the "native GUI API" in Linux. Work is being done to port GTK+ and QT to Wayland, so that current popular applications and desktop systems would need minim...
Rebasing remote branches in Git
...an clone and work on. The intermediate repository has it's master branch rebased nightly from the upstream SVN, and we are working on feature branches. For example:
...
Express.js - app.listen vs server.listen
... to provide both HTTP and HTTPS versions of your
app with the same code base, as the app does not inherit from these
(it is simply a callback):
http.createServer(app).listen(80);
https.createServer(options, app).listen(443);
The app.listen() method returns an http.Server object and (for...
Increase number of axis ticks
...
Based on Daniel Krizian's comment, you can also use the pretty_breaks function from the scales library, which is imported automatically:
ggplot(dat, aes(x,y)) + geom_point() +
scale_x_continuous(breaks = scales::pretty_break...
Filter data.frame rows by a logical condition
I want to filter rows from a data.frame based on a logical condition. Let's suppose that I have data frame like
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