Check whether array has only constant entries?
You can Apply (@@)
Equal
to your list:
constantQ = Equal@@#&;
constantQ @ {0,1,0,0}
(* False *)
or
constantQ2 = Max@#==Min@# &;
constantQ3 = Variance@#==0;
constantQ4 = Length@DeleteDuplicates@# == 1 &;
See also: SameQ
constantQ5 = SameQ @@ #&
Equal @@ {1, 1., 1}
(* True *)
SameQ @@ {1, 1., 1}
(* False *)
...
Not sure why people don't like DeleteDuplicates
:)
Length@DeleteDuplicates@arr > 1
for me this is faster than other methods (using V9 OS X tonight)
If[Length[Tally[arr]] == 1, IsConst = True, IsConst = False]