Groovy Goodness: Closed And Open Ranges
Groovy supports ranges for a long time. But Groovy 4 adds a new feature for ranges and that is the support for open (exclusive) ranges at the beginning of a range. Open means the number that defines the range is not part of the actual range result and we must use the less-than character (<). This is also referred to as exclusive, where the value is excluded from the range. When a range is closed the value is included, also called inclusive. Before Groovy 4 we could already define the end of the range to be exclusive or inclusive, but now we can also define the beginning of the range to be exclusive.
In the following example we use closed and open range definitions from the start or end:
def inclRange = 0..5
assert inclRange == [0, 1, 2, 3, 4, 5]
assert inclRange.from == 0
assert inclRange.to == 5
def exclEndRange = 0..<5
assert exclEndRange == [0, 1, 2, 3, 4]
assert exclEndRange.from == 0
assert exclEndRange.to == 4
// Support for exclusive begin added in Groovy 4.
def exclBeginRange = 0<..5
assert exclBeginRange == [1, 2, 3, 4, 5]
assert exclBeginRange.from == 1
assert exclBeginRange.to == 5
// Support for exclusive begin added in Groovy 4.
def exclRange = 0<..<5
assert exclRange == [1, 2, 3, 4]
assert exclRange.from == 1
assert exclRange.to == 4Written with Groovy 4.0.3.
