Using "Sum" (i = 1 ... N) in a function definition

*To*: mathgroup at smc.vnet.net*Subject*: [mg49666] Using "Sum" (i = 1 ... N) in a function definition*From*: wilhelm.rainer at gmx.net (Rainer)*Date*: Tue, 27 Jul 2004 07:00:44 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

I was trying to define a function using the Sum command in the following way (simplified example): MyData = {3,2,4,5,6}; MyFunc[i_] = Sum[MyData[[j]],{j,1,i}]; As you can see, the idea is to use the length of the list (i) as a variable in the function definition, such that MyFunc[1] = 3 MyFunc[2] = 3 + 2 = 5 MyFunc[3] = 3 + 2 + 4 = 9 etc. Mathematica does not like the abobe statements, and prints the following error message: "Part specification K$394 is neither an integer nor a list of integers." Does anybody know how to define (correctly) such a function. Should be possible ...? Thanks Rainer

**Follow-Ups**:**Re: Using "Sum" (i = 1 ... N) in a function definition***From:*János <janos.lobb@yale.edu>

**Re: Using "Sum" (i = 1 ... N) in a function definition***From:*DrBob <drbob@bigfoot.com>

**Re: Using "Sum" (i = 1 ... N) in a function definition***From:*Murray Eisenberg <murray@math.umass.edu>

**Re: Using "Sum" (i = 1 ... N) in a function definition***From:*Adriano Pascoletti <pascolet@dimi.uniud.it>