wes
Posts:
24
Registered:
12/13/04


List Replace Problems
Posted:
Aug 23, 2005 5:01 AM


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

