Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2008

[Date Index] [Thread Index] [Author Index]

Search the Archive

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})


  • Prev by Date: Re: Axes at the origin, for 3D plots/graphs
  • Next by Date: Re: list of dates
  • Previous by thread: Re: Re: function to check if array is empty
  • Next by thread: Re: function to check if array is empty