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Delete/Reset all entries in Core Data?
Do you know of any way to delete all of the entries stored in Core Data? My schema should stay the same; I just want to reset it to blank.
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How to exit in Node.js
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Call the global process object's exit method:
process.exit()
From the docs:
process.exit([exitcode])
Ends the process with the specified code. If omitted, exit uses the 'success' code 0.
To exit with a 'failure' code:
proces...
How to properly reuse connection to Mongodb across NodeJs application and modules
...lhost:27017";
var _db;
module.exports = {
connectToServer: function( callback ) {
MongoClient.connect( url, { useNewUrlParser: true }, function( err, client ) {
_db = client.db('test_db');
return callback( err );
} );
},
getDb: function() {
return _db;
}
};
To...
Get all object attributes in Python? [duplicate]
Is there a way to get all attributes/methods/fields/etc. of an object in Python?
4 Answers
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How does deriving work in Haskell?
Algebraic Data Types (ADTs) in Haskell can automatically become instances of some typeclasse s (like Show , Eq ) by deriving from them.
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How to use permission_required decorators on django class-based views
...ing how the new CBVs work. My question is this, I need to require login in all the views, and in some of them, specific permissions. In function-based views I do that with @permission_required() and the login_required attribute in the view, but I don't know how to do this on the new views. Is there ...
How do I raise the same Exception with a custom message in Python?
...ssign a special meaning to the elements of this tuple, while others are usually called only with a single string giving an error message.". So the code won't work arg[0] is not an error message (it could be an int, or it could be a string representing a file name).
– Trent
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putting current class as return type annotation [duplicate]
...e. Instead, they are preserved in __annotations__ in string form. This is called Postponed Evaluation of Annotations, introduced in PEP 563.
Also note:
Deprecation policy
Starting with Python 3.7, a __future__ import is required to use the
described functionality. No warnings are raised...
Proper use of beginBackgroundTaskWithExpirationHandler
...l need to wrap it in a background task. It's also very important that you call endBackgroundTask when you're finished - otherwise the app will be killed after its allotted time has expired.
Mine tend look something like this:
- (void) doUpdate
{
dispatch_async(dispatch_get_global_queue(DISPAT...
Event system in Python
...r methods', which is a
simple implementation of the Observer pattern.
Basically, the handler methods (callables) are stored in an array and are each called when the event 'fires'.
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The disadvantage of Observer event systems is that you can only register the handlers on the actual Ev...