RE: simple problem with Map?!?

*To*: mathgroup at smc.vnet.net*Subject*: [mg49496] RE: [mg49480] simple problem with Map?!?*From*: "David Park" <djmp at earthlink.net>*Date*: Thu, 22 Jul 2004 02:45:07 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Because you are mapping the function onto the elements when you really wany application to the entire list. d0 = {30, 60, 180, 60, 30}; pppp = (N[#1/Plus @@ #1] & )[d0] {0.0833333, 0.166667, 0.5, 0.166667, 0.0833333} David Park djmp at earthlink.net http://home.earthlink.net/~djmp/ From: Relishguy [mailto:relishguy at pluggedin.org] To: mathgroup at smc.vnet.net I do not understand why the last evaluation ends up screwed: In[1]:= d0 = {30,60,180,60,30}; In[2]:= tt = Plus @@ d0 Out[2]= 360 In[3]:= pp = N[d0 / tt] Out[3]= {0.0833333,0.166667,0.5,0.166667,0.0833333} In[4]:= ppp = N[d0 / (Plus @@ d0)] Out[4]= {0.0833333,0.166667,0.5,0.166667,0.0833333} In[5]:= pppp = N[# / (Plus @@ #)]& /@ d0 Out[5]= {1.,1.,1.,1.,1.} Can anyone explain this simply? Do I need Hold[] or Evaluate[] somewhere? TIA. Regards..

**Follow-Ups**:**Re: RE: simple problem with Map?!?***From:*DrBob <drbob@bigfoot.com>