Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2004
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2004

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

Search the Archive

Re: simple problem with Map?!?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg49491] Re: [mg49480] simple problem with Map?!?
  • From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
  • Date: Thu, 22 Jul 2004 02:44:57 -0400 (EDT)
  • References: <200407211040.GAA07884@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

On 21 Jul 2004, at 19:40, Relishguy wrote:

> *This message was transferred with a trial version of CommuniGate(tm) 
> Pro*
> 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..

Hold and Evaluate have nothing to do here. Neither does Map. Presumably 
what you mean is:

d0={30,60,180,60,30};


pppp=N[#/(Plus@@#)]&@d0


{0.0833333,0.166667,0.5,0.166667,0.0833333}


Andrzej Kozlowski
Chiba, Japan
http://www.mimuw.edu.pl/~akoz/


  • Prev by Date: Re: If-statement problems
  • Next by Date: AW: Plotting a contour plot with cylindrical co-ordinates
  • Previous by thread: simple problem with Map?!?
  • Next by thread: Re: simple problem with Map?!?