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Cocoa Core Data efficient way to count entities
...n do with SELECT count(1) ...). Now I just solved this task with selecting all with NSFetchedResultsController and getting the count of the NSArray ! I am sure this is not the best way...
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What is the fastest way to check if a class has a function defined?
...tr() to get the attribute, and callable() to verify it is a method:
invert_op = getattr(self, "invert_op", None)
if callable(invert_op):
invert_op(self.path.parent_op)
Note that getattr() normally throws exception when the attribute doesn't exist. However, if you specify a default value (None...
How To Change DataType of a DataColumn in a DataTable?
... of the column after the DataTable is filled, you can change it after you call FillSchema, but before you call Fill. For example, say the 3rd column is the one you want to convert from double to Int32, you could use:
adapter.FillSchema(table, SchemaType.Source);
table.Columns[2].DataType = typeof (...
Is MonoTouch now banned on the iPhone? [closed]
... C# then it would be violating the license:
...Applications must be originally written in Objective-C, C, C++, or JavaScript as executed by the iPhone OS WebKit engine...
They even hammer it in a little further:
Applications that link to Documented APIs through an intermediary translation or comp...
Handling specific errors in JavaScript (think exceptions)
...they also explain how to make it conform, though it's not as succint. Basically same as above, but using instanceOf. Check here
– Bart
Oct 20 '15 at 8:58
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Are Swift variables atomic?
... you, i.e.:
class Car {
static let sharedCar: Car = Car() // will be called inside of dispatch_once
}
private let sharedCar: Car2 = Car2() // same here
class Car2 {
}
Update 05/25/16: Keep an eye out for swift evolution proposal https://github.com/apple/swift-evolution/blob/master/proposals...
Port 80 is being used by SYSTEM (PID 4), what is that?
...P adress is 0.0.0.0, state = LISTENING: means that port 80 is listening to all interfaces (not used)
How to read NETSTAT -AN results:
https://sites.google.com/site/xiangyangsite/home/technical-tips/linux-unix/networks-related-commands-on-linux/how-to-read-netstat--an-results
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MySQL Cannot drop index needed in a foreign key constraint
...
You have to drop the foreign key. Foreign keys in MySQL automatically create an index on the table (There was a SO Question on the topic).
ALTER TABLE mytable DROP FOREIGN KEY mytable_ibfk_1 ;
share
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Length of a JavaScript object
...an break enumerations in various libraries. Adding methods to Object is usually safe, though.
Here's an update as of 2016 and widespread deployment of ES5 and beyond. For IE9+ and all other modern ES5+ capable browsers, you can use Object.keys() so the above code just becomes:
var size = Object...
C++ map access discards qualifiers (const)
...k up a key without modifying the map.
find() returns an iterator, or const_iterator to an std::pair containing both the key (.first) and the value (.second).
In C++11, you could also use at() for std::map. If element doesn't exist the function throws a std::out_of_range exception, in contrast to o...