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Difference between Django's annotate and aggregate methods?
...rage_price': 34.35}
Returns a dictionary containing the average price of all books in the queryset.
Annotation
>>> q = Book.objects.annotate(num_authors=Count('authors'))
>>> q[0].num_authors
2
>>> q[1].num_authors
1
q is the queryset of books, but each book has been...
How to get Scala List from Java List?
...now built into the language using:
import scala.collection.JavaConversions._
...
lst.toList.foreach{ node => .... }
works. asScala did not work
In 2.12.x use import scala.collection.JavaConverters._
In 2.13.x use import scala.jdk.CollectionConverters._
...
How to access component methods from “outside” in ReactJS?
...
class Parent extends React.Class {
constructor(props) {
this._child = React.createRef();
}
componentDidMount() {
console.log(this._child.current.someMethod()); // Prints 'bar'
}
render() {
return (
<div>
<Child ref=...
C++ convert hex string to signed integer
...>> x;
// output it as a signed type
std::cout << static_cast<int>(x) << std::endl;
}
In the new C++11 standard, there are a few new utility functions which you can make use of! specifically, there is a family of "string to number" functions (http://en.cppreference.c...
UICollectionView reloadData not functioning properly in iOS 7
...nd probing. I feel this is an iOS 7 bug. Forcing the main thread will run all UIKit related messages. I seem to run into this when popping to the view from another view controller. I refresh the data on viewWillAppear. I could see the data and collection view reload call, but the UI was not updat...
What's the scope of a variable initialized in an if statement?
...ked only at runtime -- that is, when you get to the print x statement. If __name__ didn't equal "__main__" then you would get an exception: NameError: name 'x' is not defined.
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✔ Checkmark selected row in UITableViewCell
...
Update Swift 4
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.cellForRow(at: indexPath)?.accessoryType = .checkmark
}
func tableView(_ tableView: UITableView, didDeselectRowAt indexPath: IndexPat...
What is exactly the base pointer and stack pointer? To what do they point?
Using this example coming from wikipedia, in which DrawSquare() calls DrawLine(),
8 Answers
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Insert HTML with React Variable Statements (JSX)
... return (
<div className="content" dangerouslySetInnerHTML={{__html: thisIsMyCopy}}></div>
);
}
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How to export collection to CSV in MongoDB?
How do you export all the records in a MongoDB collection to a .csv file?
11 Answers
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