from itertools import groupby
arr = [1.112, 1.113, 1.114, 1.111, 1.221, 1.223, 1.321, 1.021, 1.03, 2.0, 3.6, 4.2]
result = groupby(arr, key=lambda x: int(x * 10) if 1 <= x < 2 else -1)
for key, vals in result:
print(key / 10, list(vals))
ZnJvbSBpdGVydG9vbHMgaW1wb3J0IGdyb3VwYnkKCmFyciA9IFsxLjExMiwgMS4xMTMsIDEuMTE0LCAxLjExMSwgMS4yMjEsIDEuMjIzLCAxLjMyMSwgMS4wMjEsIDEuMDMsIDIuMCwgMy42LCA0LjJdCgoKcmVzdWx0ID0gZ3JvdXBieShhcnIsIGtleT1sYW1iZGEgeDogaW50KHggKiAxMCkgaWYgMSA8PSB4IDwgMiBlbHNlIC0xKQoKZm9yIGtleSwgdmFscyBpbiByZXN1bHQ6CglwcmludChrZXkgLyAxMCwgbGlzdCh2YWxzKSk=