Loop Counter

The convenient loop counter of slices is not automatic for other types. Loop counter can be achieved for user-defined types in different ways depending on whether the foreach support is provided by range member functions or by opApply overloads.

Loop counter with range functions

If foreach support is provided by range member functions, then a loop counter can be achieved simply by enumerate from the std.range module:

import std.range; 

// ...

foreach (i, element; NumberRange(42, 47).enumerate) {
    writefln("%s: %s", i, element); 
}

enumerate is a range that produces consecutive numbers ...