Re: function to check if array is empty
- To: mathgroup at smc.vnet.net
- Subject: [mg88384] Re: function to check if array is empty
- From: Bill Rowe <readnews at sbcglobal.net>
- Date: Sat, 3 May 2008 06:18:50 -0400 (EDT)
On 5/1/08 at 3:22 AM, willpowers69 at hotmail.com (will parr) wrote:
>i'm looking for a function to return either True (or 1), or False
>(or 0) when it checks an array. eg:
>X = Array[0 &, {3, 3}]
>then test with function (called ArrayEmpty, for example)
>In: ArrayEmpty[X]
>Out: True
I would not consider an array where every element is zero an
empty array. For a truly empty array
emptyArrayQ[x_] := Flatten@x == {}
for an array where every element is zero
zeroArrayQ[
x_] := {} == (SparseArray[x] /.
HoldPattern[SparseArray[_, _, _, {_, {_, a_}, b_}]] :>
Flatten@{a, b})