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

*To*: mathgroup at smc.vnet.net*Subject*: [mg127169] Re: Modifying an entry in array specified by a list of arbitrary length*From*: Bill Rowe <readnews at sbcglobal.net>*Date*: Thu, 5 Jul 2012 06:10:32 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

On 7/4/12 at 3:32 AM, samid.hoda at gmail.com wrote: >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? In[1]:= data = RandomReal[1, 5]; data + SparseArray[{2 -> 1}, Length@data] Out[2]= {0.792931,1.11432,0.235235,0.730301,0.48574}