Range expansion
Range expansion
You are encouraged to solve this task according to the task description, using any language you may know.
You are encouraged to solve this task according to the task description, using any language you may know.
A format for expressing an ordered list of integers is to use a comma separated list of either
- individual integers
- Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
- The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
- -6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
- -6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
The task
Is to expand the range description:
- -6,-3-1,3-5,7-11,14,15,17-20
ALGOL 68
<lang algol68>MODE YIELDINT = PROC(INT)VOID;
MODE RANGE = STRUCT(INT lwb, upb); MODE RANGEINT = UNION(RANGE, INT);
OP SIZEOF = ([]RANGEINT list)INT: (
- determine the length of the output array #
INT upb := LWB list - 1; FOR key FROM LWB list TO UPB list DO CASE list[key] IN (RANGE value): upb +:= upb OF value - lwb OF value + 1, (INT): upb +:= 1 ESAC OD; upb
);
PROC gen range expand = ([]RANGEINT list, YIELDINT yield)VOID:
FOR key FROM LWB list TO UPB list DO CASE list[key] IN (RANGE range): FOR value FROM lwb OF range TO upb OF range DO yield(value) OD, (INT int): yield(int) ESAC OD;
PROC range expand = ([]RANGEINT list)[]INT: (
- Finally full the output array with a generator #
[LWB list: LWB list + SIZEOF list - 1]INT out; INT upb := LWB out - 1;
- FOR INT value IN # gen range expand(list, # ) DO #
- (INT value)VOID:
out[upb +:= 1] := value
- OD #);
out
);
test:(
[]RANGEINT list = (-6, RANGE(-3, 1), RANGE(3, 5), RANGE(7, 11), 14, 15, RANGE(17, 20)); print((range expand(list), new line))
)</lang> Output:
-6 -3 -2 -1 +0 +1 +3 +4 +5 +7 +8 +9 +10 +11 +14 +15 +17 +18 +19 +20
Python
<lang python>def rangeexpand(txt):
lst = [] for r in txt.split(','): if '-' in r[1:]: r0, r1 = r[1:].split('-', 1) lst += range(int(r[0] + r0), int(r1) + 1) else: lst.append(int(r)) return lst
print(rangeexpand('-6,-3-1,3-5,7-11,14,15,17-20'))</lang>
Sample output
[-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20]