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+--- Thread: list slicing question (/thread-19193.html)
list slicing question - Albert Chan - 11-23-2022 02:55 PM
I wanted to translate XCas code to HP Prime Cas, and have problem translate a[::n]
XCas> range(7)[::2] → [0, 2, 4, 6]
Here, XCas behave like Python:
>>> range(7)[::2]
[0, 2, 4, 6]
>>> range(7)[0:None:2] # explicitly showing defaults
[0, 2, 4, 6]
HP Prime Cas, however, is 1 based. (list last index has unintuitive -1 + 1 = 0)
CAS> range(7)[::2] --> range(7)[1:0:2] --> [0,2,4]
Is there an equivalent to Python's None ?
RE: list slicing question - Albert Chan - 11-24-2022 12:04 AM
By trial and error, this seems to work, but weird, with 1 = beyond end-of-list
CAS> range(7)[1:1:2] → [0,2,4,6]
CAS> range(7)[2:1:2] → [1,3,5]
CAS> range(7)[3:1:2] → [2,4,6]
RE: list slicing question - Albert Chan - 11-24-2022 11:32 AM
(11-24-2022 12:04 AM)Albert Chan Wrote: By trial and error, this seems to work, but weird, with 1 = beyond end-of-list
At least it is consistently weird, for 0-based XCas, 0 = beyond end-of list
XCas> range(7)[0:0:2] → [0,2,4,6]
XCas> range(7)[1:0:2] → [1,3,5]
XCas> range(7)[2:0:2] → [2,4,6]