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What's the difference between Ruby's dup and clone methods?
...does not.
o = Object.new
def o.foo
42
end
o.dup.foo # raises NoMethodError
o.clone.foo # returns 42
Second, clone preserves the frozen state, while dup does not.
class Foo
attr_accessor :bar
end
o = Foo.new
o.freeze
o.dup.bar = 10 # succeeds
o.clone.bar = 10 # raises RuntimeError
The...
How to make node.js require absolute? (instead of relative)
... searches these paths in order, stopping at the first match and raising an error if nothing is found:
/beep/boop/node_modules/xyz
/beep/node_modules/xyz
/node_modules/xyz
For each xyz directory that exists, node will first look for a xyz/package.json to see if a "main" field exists. The "main" fi...
Cluster analysis in R: determine the optimal number of clusters
...1)*i^2))))
plot(d)
One. Look for a bend or elbow in the sum of squared error (SSE) scree plot. See http://www.statmethods.net/advstats/cluster.html & http://www.mattpeeples.net/kmeans.html for more. The location of the elbow in the resulting plot suggests a suitable number of clusters for th...
Unknown file type MIME?
... Thanks! application/unknown is working great, octet-stream results an error in chrome at my sample png-file!
– fnkr
May 12 '13 at 13:34
10
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What is a callback function?
... another is called in the event that the parent function throws a specific error, etc).
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How do you print in a Go test using the “testing” package?
...sing default formatting, analogous to Println, and records the text in the error log. For tests, the text will be printed only if the test fails or the -test.v flag is set. For benchmarks, the text is always printed to avoid having performance depend on the value of the -test.v flag.
...
What is the concept of erasure in generics in Java?
...nerics, mind you.) Type erasure is the source of many of the "odd" warning/error messages when dealing with Java generics.
Other resources:
Oracle documentation
Wikipedia
Gilad Bracha's Java generics guide (PDF - highly recommended; link may need to change periodically)
Angelika Langer's Java Gen...
Why is String immutable in Java?
...
The DZone article contains major errors about the operation of the Strign pool. It is only for constants. Ergo the stated rationale is invalid.
– Marquis of Lorne
Feb 13 '19 at 9:51
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How do I use a custom deleter with a std::unique_ptr member?
...nique<Bar>() {
auto p = create();
if (!p) throw std::runtime_error("Could not `create()` a new `Bar`.");
return { p };
}
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Why does an overridden function in the derived class hide other overloads of the base class?
...b)
{
a.copy(&b); // ok: copy Base part of b
b.copy(&a); // error: copy(Base*) is hidden by copy(Derived*)
}
Without this rule, b's state would be partially updated, leading to slicing.
This behavior was deemed undesirable when the language was designed. As a better approach, it wa...