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How to create NS_OPTIONS-style bitmask enumerations in Swift?
...tains(.secondOption) {
print("multipleOptions has SecondOption")
}
let allOptions = MyOptions(rawValue: 7)
if allOptions.contains(.thirdOption) {
print("allOptions has ThirdOption")
}
Swift 2.0
In Swift 2.0, protocol extensions take care of most of the boilerplate for these, which are now...
编译失败！ Error: Your build failed due to an error in the AAPT stage,...
...tivity> attribute name has invalid character
[java] /tmp/1685410160630_0.39828964915976717-0/youngandroidproject/../build/AndroidManifest.xml:5: Tag <activity> attribute name has invalid character '�'.
[java] May 30, 2023 9:29:27 AM com.google.appinventor.build...
How is __eq__ handled in Python and in what order?
...
The a == b expression invokes A.__eq__, since it exists. Its code includes self.value == other. Since int's don't know how to compare themselves to B's, Python tries invoking B.__eq__ to see if it knows how to compare itself to an int.
If you amend your ...
Vagrant error : Failed to mount folders in Linux guest
...
The plugin vagrant-vbguest solved my problem:
$ vagrant plugin install vagrant-vbguest
Output:
$ vagrant reload
==> default: Attempting graceful shutdown of VM...
...
==> default: Machine booted and ready!
GuestAdditions 4.3.12 running --- OK.
==> default: Checking for guest addi...
Curly braces in string in PHP
...nterpolation. From the manual:
Complex (curly) syntax
This isn't called complex because the syntax is complex, but because
it allows for the use of complex expressions.
Any scalar variable, array element or object property with a string
representation can be included via this synta...
What is __future__ in Python used for and how/when to use it, and how it works
__future__ frequently appears in Python modules. I do not understand what __future__ is for and how/when to use it even after reading the Python's __future__ doc .
...
How to return a value from __init__ in Python?
I have a class with an __init__ function.
10 Answers
10
...
What are the rules for calling the superclass constructor?
What are the C++ rules for calling the superclass constructor from a subclass one?
10 Answers
...
How is Perl's @INC constructed? (aka What are all the ways of affecting where Perl modules are searc
What are all the ways of affecting where Perl modules are searched for?
or, How is Perl's @INC constructed ?
3 Answers
...
Select distinct values from a table field
...ant any ordering to be applied to a query, not even the default ordering, call order_by() with no parameters.
and distinct() in the note where it discusses issues with using distinct() with ordering.
To query your DB, you just have to call:
models.Shop.objects.order_by().values('city').distinct(...