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Property getters and setters
...g to backup the computed property. Try this:
class Point {
private var _x: Int = 0 // _x -> backingX
var x: Int {
set { _x = 2 * newValue }
get { return _x / 2 }
}
}
Specifically, in the Swift REPL:
15> var pt = Point()
pt: Point = {
_x = 0
}
16> pt.x = 10...
Which is fastest? SELECT SQL_CALC_FOUND_ROWS FROM `table`, or SELECT COUNT(*)
When you limit the number of rows to be returned by a SQL query, usually used in paging, there are two methods to determine the total number of records:
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CGContextDrawImage draws image upside down when passed UIImage.CGImage
...answered Feb 6 '09 at 20:46
Kendall Helmstetter GelnerKendall Helmstetter Gelner
72.5k2626 gold badges123123 silver badges146146 bronze badges
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Python loop that also accesses previous and next values
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The edited version of this is still not logically sound: At the end of the loop obj and next_ will be the same object for the last iteration, which may have unintended side effects.
– TemporalWolf
Dec 5 '17 at 22:01
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Determine project root from a running node.js application
...uire.main === module
Because module provides a filename property (normally equivalent to __filename), the entry point of the current application can be obtained by checking require.main.filename.
So if you want the base directory for your app, you can do:
var path = require('path');
var appD...
Check if a number is int or float
...>> if isinstance(x, int):
print 'x is a int!'
x is a int!
_EDIT:_
As pointed out, in case of long integers, the above won't work. So you need to do:
>>> x = 12L
>>> import numbers
>>> isinstance(x, numbers.Integral)
True
>>> isinstance(x, int)
F...
Aren't Python strings immutable? Then why does a + “ ” + b work?
...the variable a to point at a new string "Dog eats treats". You didn't actually mutate the string "Dog". Strings are immutable, variables can point at whatever they want.
share
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improve this answe...
Saving a Numpy array as an image
... Remember to scale the values to the right range for PNG, usually 0..255. The value ranges in neural networks are frequently 0..1 or -1..1.
– Tomáš Gavenčiak
Mar 31 '18 at 18:49
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How do I bind a WPF DataGrid to a variable number of columns?
... property is ReadOnly, like everyone noticed, I made an Attached Property called BindableColumns which updates the Columns in the DataGrid everytime the collection changes through the CollectionChanged event.
If we have this Collection of DataGridColumn's
public ObservableCollection<DataGrid...
Best way to give a variable a default value (simulate Perl ||, ||= )
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In PHP 7 we finally have a way to do this elegantly. It is called the Null coalescing operator. You can use it like this:
$name = $_GET['name'] ?? 'john doe';
This is equivalent to
$name = isset($_GET['name']) ? $_GET['name']:'john doe'...