Szathmáry László honlapja @ DEIK

range

Warning! C#'s range is different from Python's range!

csharp> Enumerable.Range(0, 10)
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 } // Seems good, right?

csharp> Enumerable.Range(12, 15)
{ 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26 } // Ooops! What da hell?

csharp> Enumerable.Range(12, 3)
{ 12, 13, 14 } // Start at 12 and produce 3 consecutive numbers.

Range has 2 parameters: start position and count. Thus Range(12, 15) means to start at 12 and enumerate 15 numbers altogether.

To simulate Python's range, I have this solution:

public static class Py
{
// make a range over [start..end) , where end is NOT included (exclusive)
public static IEnumerable<int> RangeExcl(int start, int end)
{
if (end <= start) return Enumerable.Empty<int>();
// else
return Enumerable.Range(start, end - start);
}

// make a range over [start..end] , where end IS included (inclusive)
public static IEnumerable<int> RangeIncl(int start, int end)
{
return RangeExcl(start, end + 1);
}
}

Usage:

Py.RangeExcl(10, 15) // 10, 11, 12, 13, 14

Py.RangeIncl(10, 15) // 10, 11, 12, 13, 14, 15

See the current version here.

20180403c

range