Re: MemberQ

*To*: mathgroup at smc.vnet.net*Subject*: [mg68533] Re: MemberQ*From*: "Scout" <Scout at nodomain.com>*Date*: Wed, 9 Aug 2006 04:18:55 -0400 (EDT)*References*: <eb9pkt$t4j$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

"Bruce Colletti" <vze269bv at verizon.net> news:eb9pkt$t4j$1 at smc.vnet.net... > Re Mathematica 5.2.0.0. > > Since 0.7 is in the set {0.0, 0.1, 0.2,..., 0.9, 1.0}, why does > MemberQ[Range[0., 1., .1], .7] return False? > > Thankx. > > Bruce > Hi Bruce, you could have strange behaviors if you try to compare real numbers. It could happen that on different systems that equality gives True. I suggest you to use an alternative representation for Reals or to try to use the operator == with commands such as Rationalize[], Round[], Chop [], N [], etc. Using exact Rational numbers: In[]:= i=Range[0, 1, 1/10]; In[]:= MemberQ[i, 7/10] Out[]= True HTH, ~Scout~