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Covariance and contravariance real world example
...) // "Melman"
};
PrintLifeForms(myGiraffes); // Compile Error!
cannot convert from 'System.Collections.Generic.List<Giraffe>' to 'System.Collections.Generic.IList<LifeForm>'
Why? Because the generic parameter IList<LifeForm> is not covariant -
IList<T> is invariant, s...
Sort points in clockwise order?
...y done in any language. The formulas can be found in this section.
After converting to polar coordinates, just sort by the angle, theta.
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How do I iterate over an NSArray?
...rray
double machTimerMillisMult; // multiplier to convert mach_absolute_time() to milliseconds
IBOutlet UISlider *sliderCount;
IBOutlet UILabel *labelCount;
IBOutlet UILabel *labelResults;
}
-(IBAction) doNSArray:(id)sender;
-(IBActi...
How do I measure time elapsed in Java? [duplicate]
...- starts;
}
public long time(TimeUnit unit) {
return unit.convert(time(), TimeUnit.MILLISECONDS);
}
}
Usage:
TimeWatch watch = TimeWatch.start();
// do something
long passedTimeInMs = watch.time();
long passedTimeInSeconds = watch.time(TimeUnit.SECONDS);
Aft...
C pointers : pointing to an array of fixed size
...re illegal. However, we know in practice that you can always automatically convert from char* to char const* without warning. IMO, clang is more consistent in allowing this than gcc is, though I agree with you that the spec seems to prohibit any of these automatic conversions.
–...
How do I check if a string is valid JSON in Python?
... #prints True
print is_json('{"foo":[5,6.8],"foo":"bar"}') #prints True
Convert a JSON string to a Python dictionary:
import json
mydict = json.loads('{"foo":"bar"}')
print(mydict['foo']) #prints bar
mylist = json.loads("[5,6,7]")
print(mylist)
[5, 6, 7]
Convert a python object to JSON str...
Why use the SQL Server 2008 geography data type?
...lDegrees = 1
Begin
set @X = 1
END
Else
Begin
set @X = 24
End
-- convert to decimal degrees
set @Lat1 = @Latitude1 * @X
set @Long1 = @Longitude1 * @X
set @Lat2 = @Latitude2 * @X
set @Long2 = @Longitude2 * @X
-- convert to radians: radians = (degrees/180) * PI
set @Lat1 = (@Lat1 / 180) * @...
Set focus on TextBox in WPF from view model
...perty of the control I want to shift the focus to is tied to a multi-value converter. Apparently, the GotFocus event handler gets called before the multi-value converter does...which means the control, at that point, is disabled, so as soon as GotFocus completes, LostFocus gets called (I guess becau...
Populate data table from data reader
...
Please check the below code. Automatically it will convert as DataTable
private void ConvertDataReaderToTableManually()
{
SqlConnection conn = null;
try
{
string connString = ConfigurationManager.ConnectionStrings["NorthwindConn"].Conn...
What is “lifting” in Scala?
...e, suppose you have a function which returns an IO[Stream[A]]. This can be converted to the monad transformer StreamT[IO, A]. Now you may wish to "lift" some other value an IO[B] perhaps to that it is also a StreamT. You could either write this:
StreamT.fromStream(iob map (b => Stream(b)))
Or ...