Re: List Replace Problems
- To: mathgroup at smc.vnet.net
- Subject: [mg59845] Re: List Replace Problems
- From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
- Date: Wed, 24 Aug 2005 06:30:12 -0400 (EDT)
- Organization: Uni Leipzig
- References: <deeom3$3rl$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi, dlst need the attribute hold First otherwise u is evaluated and there is no memory location where your assimgment is stored. Regards Jens "wesh" <wesh at acm.org> schrieb im Newsbeitrag news:deeom3$3rl$1 at smc.vnet.net... | | I want to perform some element by element operations on a class of | lists. For a given list The operation in a much simplified form can be | characterized by | | a = {1, 3, 5, 7, 9}; | Do[a[[i]] /= i, {i, 1, 5}]; | a | | Out[38]= | {1, 3/2, 5/3, 7/4, 9/5} | | Now, however, if I try to define a function to do this for a general | list, namely, | | dlst[u_List] = | Do[u[[i]] /= i, {i, 1, 5}]; | a = {1, 3, 5, 7, 9}; | dlst[a]; | a | | Set::setps: | ({1, 2, 3, 4, 5}) in assignment of part is not a symbol. ! More ... | | Out[39]= | {1, 3, 5, 7, 9} | | I get the above error. It says I'm trying to assign one number to | another number. Why does Mathematica perform in the first case but | refuse to in the second. | | I tried | | b = Do[ReplacePart[a, a[[i]]/i, i], {i, 1, 5}] | | but it doesn't even bother to return an error message. | | | How, can I get the desired function? | | Thanks, | | Wesh |