In a brief, there are two key points: The toString method of an empty array returns an empty string. An empty string coerces to zero using the unary plus operator or the Number constructor called as a function (e.g. +”” === 0;). For example, we can use an object that defines a toString method, and … Read more
How about this? val pair = query.getSingleOrNone pair collect { case Array(x: MyClass1, y: MyClass2, _*) => (x,y) } // result would be Option[(MyClass1, MyClass2)]
For others, this works: //If you get ‘dllimport unknown’-, then add ‘using System.Runtime.InteropServices;’ [DllImport(“gdi32.dll”, EntryPoint = “DeleteObject”)] [return: MarshalAs(UnmanagedType.Bool)] public static extern bool DeleteObject([In] IntPtr hObject); public ImageSource ImageSourceFromBitmap(Bitmap bmp) { var handle = bmp.GetHbitmap(); try { return Imaging.CreateBitmapSourceFromHBitmap(handle, IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions()); } finally { DeleteObject(handle); } }
Why is this a narrowing conversion? Because the definition includes (with my emphasis): C++11 8.5.4/7 A narrowing conversion is an implicit conversion […] from an integer type […] to a floating-point type, except where the source is a constant expression and the actual value after conversion will fit into the target type and will produce … Read more
Yes OpenCV is more robust and flexible and can perform most of the image processing routines which are available out there, So probably this filter can be done with OpenCV> However, there may not be a straightforward API for that. Anyways, as far as the conversion of image format from OpenCV to PIL is concerned … Read more
I experimented with solutions using lookup tables, but found them fraught with issues, and actually not very fast. The fastest solution turned out to be the least imaginitive: int fast_atoi( const char * str ) { int val = 0; while( *str ) { val = val*10 + (*str++ – ‘0’); } return val; } … Read more
When you type x = 0 that is creating a new int variable (name) and assigning a zero to it. When you type x[age1] that is trying to access the age1‘th entry, as if x were an array.
C++11 introduces std::stoi (and variants for each numeric type) and std::to_string, the counterparts of the C atoi and itoa but expressed in term of std::string. #include <string> std::string s = std::to_string(42); is therefore the shortest way I can think of. You can even omit naming the type, using the auto keyword: auto s = std::to_string(42); … Read more
Spec: Conversions: Specific rules apply to (non-constant) conversions between numeric types or to and from a string type. These conversions may change the representation of x and incur a run-time cost. All other conversions only change the type but not the representation of x. So converting to and from the underlying type of your custom … Read more