Re: Modifying an entry in array specified by a list of arbitrary length

*To*: mathgroup at smc.vnet.net*Subject*: [mg127182] Re: Modifying an entry in array specified by a list of arbitrary length*From*: Bob Hanlon <hanlonr357 at gmail.com>*Date*: Thu, 5 Jul 2012 06:15:02 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

x = Array[a, {4, 3, 5}]; i = {1, 2, 3}; Element to be modified x[[Sequence @@ i]] a[1, 2, 3] Change element x[[Sequence @@ i]] += 1 1 + a[1, 2, 3] Verifying that array was modified x[[Sequence @@ i]] 1 + a[1, 2, 3] Bob Hanlon On Wed, Jul 4, 2012 at 3:32 AM, <samid.hoda at gmail.com> wrote: > Hi, > > I want to edit an element whose position is specified by an arbitrary list that is a result of a computation (the list is not of fixed length). Something like > > i = {1,2,3} > Extract[X,i]+=1 > > except that Extract passes X by value instead of by reference. Anyone have any ideas? > > Thanks, > Sam >