Re: IsExact

*To*: mathgroup at smc.vnet.net*Subject*: [mg80546] Re: IsExact*From*: Albert <awnl at arcor.net>*Date*: Sun, 26 Aug 2007 02:55:29 -0400 (EDT)*References*: <falsi4$gfh$1@smc.vnet.net>

carlos at colorado.edu wrote: > Let c be a 1D list of scalar coefficients, numeric or symbolic, > real or complex. No entry is a list. Examples: > > ClearAll[n,x,y,a,a1,a2,b,r]; > c1={1,2*I/5,E^(25*n),3/4+I,Cos[n*x*Pi],y*Sqrt[-5]}; > c2={a/b,r+2/5,a1,,,,,a2}; > c3={1.5,0,Sqrt[3],0,4}; > c4={(r+0.5)/3,3/7,3+Sin[4*x*y]}; > c5={1,2,3,4,5,6}+0.0; > c6={N[x]}; > > I need a function IsExact[c] that returns False if > at least one entry of c is floating, or if it contains one > floating number; else True. For example, tests on > c1 and c2 should return True; the others False. > my 2 cent: IsExactQ[x_] := (Length[Cases[x, _Real, Infinity]] == 0) it doesn't get the last one right, if x is not set to any value. But this will not be possible, since c6 doesn't know anything about N having been applied to x... hth, albert