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Why is Scala's immutable Set not covariant in its type?
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Set is invariant in its type parameter because of the concept behind sets as functions. The following signatures should clarify things slightly:
trait Set[A] extends (A=>Boolean) {
def apply(e: A): Boolean
}
If Set w...
How can I create a Set of Sets in Python?
I'm trying to make a set of sets in Python. I can't figure out how to do it.
5 Answers
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How to set 'auto' for upper limit, but keep a fixed lower limit with matplotlib.pyplot
I want to set the upper limit of the y-axis to 'auto', but I want to keep the lower limit of the y-axis to always be zero. I tried 'auto' and 'autorange', but those don't seem to work. Thank you in advance.
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Why is '+' not understood by Python sets?
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Python sets don't have an implementation for the + operator.
You can use | for set union and & for set intersection.
Sets do implement - as set difference. You can also use ^ for symmetric set difference (i.e., it will return ...
How to enable C++11/C++0x support in Eclipse CDT?
...s for me. I am using Eclipse Indigo 20110615-0604 on Windows with a Cygwin setup.
Make a new C++ project
Default options for everything
Once created, right-click the project and go to "Properties"
C/C++ Build -> Settings -> Tool Settings -> GCC C++ Compiler -> Miscellaneous -> Othe...
What are 'get' and 'set' in Swift?
...n to simple properties that are stored, properties can have a getter and a setter.
class EquilateralTriangle: NamedShape {
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When some other class wants to get that perimeter variable, they do this:
let someVar = myTriangle.perimeter
... Which calls this:
get{
return 3.0 * self.sideLen...
Does PowerShell support constants?
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Use
Set-Variable test -option Constant -value 100
or
Set-Variable test -option ReadOnly -value 100
The difference between "Constant" and "ReadOnly" is that a read-only variable can be removed (and then re-created) via
Remov...
Python's “in” set operator
I'm a little confused about the python in operator for sets.
5 Answers
5
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Different types of thread-safe Sets in Java
... to be a lot of different implementations and ways to generate thread-safe Sets in Java.
Some examples include
4 Answers
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How can I add items to an empty set in python
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D = {} is a dictionary not set.
>>> d = {}
>>> type(d)
<type 'dict'>
Use D = set():
>>> d = set()
>>> type(d)
<type 'set'>
>>> d.update({1})
>>> d.add(2)
>>> d.update([3,3...