python - Infinite cycle over a range starting at a particular number -


say have range:

r = range(1, 6)

using range, want cycle infinitely , yield numbers come:

for in cycle(r):     yield(i)

this correctly produce values of:

1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, ...

however, want start yielding specific value continue on range it's defined. is, if want start @ 3, sequence be:

3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, ...

is there way combination of range , cycle (or other way)?

just dropwhile until reach first value want emit:

>>> itertools import cycle, dropwhile >>> iterable = dropwhile(lambda x: x < 3, cycle(range(1, 6))) >>> _ in range(10): ...     print(next(iterable)) ... 3 4 5 1 2 3 4 5 1 2

per docs (emphasis mine):

make iterator drops elements iterable long predicate true; afterwards, returns every element.

the predicate takes effect until first value evaluates false-y.


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