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Re: Assigning Values to Many Symbols at Once

  • To: mathgroup at
  • Subject: [mg101823] Re: Assigning Values to Many Symbols at Once
  • From: Bill Rowe <readnews at>
  • Date: Sat, 18 Jul 2009 04:51:12 -0400 (EDT)

On 7/16/09 at 8:22 AM, gregory.lypny at (Gregory Lypny)

>Leonid and Zach, both of you suggested direct list-to-list
>assignments, which is what I thought should work but does not with
>you create the list of new symbols using Table or mapping.  It does
>work if you create the symbol list manually,  For example, typing

>{x1, x2} = {9, 11}

>works as expected, creating two new symbols, x1 with a value of 9
>and x2 with a value of 10.  However,

>Table[Symbol["x" <> ToString[i]], {i, 5}] = {1,2,3,4,5}



>result in the error message

>Set::write: Tag Table in Table[Symbol[xabc<>ToString[i]],{i,5}] is

This works with no error message

In[1]:= Evaluate[ToExpression[Table["x" <> ToString[n], {n,
5}]]] =

Out[1]= {1,2,3,4,5}

In[2]:= x1

Out[2]= 1

or you can do

In[3]:= Evaluate[Table[Symbol["y"<>ToString[n]], {n, 5}]] = {1,2,3,4,5}

Out[3]= {1,2,3,4,5}

In[4]:= y1

Out[4]= 1

and get no error message.

Note, both of these examples assume the variables do not
currently exist and have assigned values.

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