Re: Help please: Summing a list
- To: mathgroup at smc.vnet.net
- Subject: [mg13501] Re: Help please: Summing a list
- From: Paul Abbott <paul at physics.uwa.edu.au>
- Date: Fri, 31 Jul 1998 04:33:18 -0400
- Organization: University of Western Australia
- References: <6pebm8$i6j@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
robpeterson at iname.com wrote:
> I make a list of numbers, eg:
>
> P=Table[6,{x,0,110}]; (I have a more interesting list to use later if I
> get this working)
>
> Now I want to make another list PP in which each entry PP[[i]] is the
> sum of P's first i entries.
For the list (it is safer to use lower-case variables),
In[1]:= p = Table[6, {x, 0, 10}];
FoldList is probably the easiest (and fastest) operator for producing
the list of cumulative sums:
In[2]:= FoldList[Plus, First[P], Rest[P]];
Out[2]= {6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66}
Cheers,
Paul
____________________________________________________________________
Paul Abbott Phone: +61-8-9380-2734
Department of Physics Fax: +61-8-9380-1014
The University of Western Australia Nedlands WA 6907
mailto:paul at physics.uwa.edu.au AUSTRALIA
http://www.pd.uwa.edu.au/~paul
God IS a weakly left-handed dice player
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