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Re: local variables - Module, For loop

  • To: mathgroup at smc.vnet.net
  • Subject: [mg113043] Re: local variables - Module, For loop
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Tue, 12 Oct 2010 04:24:36 -0400 (EDT)

f[x_] := Module[{i}, For[i = 0, i != x, i++, Print[i]]]

f[5]

Don't use a For loop and you won't need the "throw-away-variable"

f[x_] := Print /@ Range[0, x - 1]

f[5];

Print is often unnecessary. If you want to display the results in a column, use Column

f[x_] := Range[0, x - 1]

f[5] // Column


Bob Hanlon

---- Sebastian Schmitt <sschmitt at physi.uni-heidelberg.de> wrote: 

=============
Dear all!

(I recycle my disclaimer.)

I'm new to Mathematica with a background mostly in C++. Many times I
have the impression that my style is not natural-Mathematica
(Mathematicaesque so to say).

If I have a For loop in a function like this:

In[39]:= f[x_] := Module[{},
  For[i = 0, i != x, i++,
   Print[i]
   ]
  ]

In[41]:= f[2]

During evaluation of In[41]:= 0

During evaluation of In[41]:= 1

In[42]:= i

Out[42]= 2

I was surprised to find "i" being not local to the For loop. Do I have
to keep track of all my throw-away-variables and put them in the list of
local variables of the Module? I find it pretty tedious. Is there a
better way?

Thanks in advance,

Sebastian



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