September 2017 Update

Task/Combinations/Jq/combinations.jq

@@ -0,0 +1,9 @@
+def combination(r):
+  if r > length or r < 0 then empty
+  elif r == length then .
+  else  ( [.[0]] + (.[1:]|combination(r-1))),
+        ( .[1:]|combination(r))
+  end;
+
+# select r integers from the set (0 .. n-1)
+def combinations(n;r): [range(0;n)] | combination(r);