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I am trying to do something which I assume should be very simple: I want to generate a list with symbolic coefficients that looks like this:

A = {a0, a1, a2, a3, ... , a20};

And I mean to do this a lot up to an arbitrary number, so I wouldn't want to type them all. So of course when I set one of them, say a1 = 5, then it should be updated in the list, so now:

A = {a0, 5, a2, a3, ... , a20};

I might just be missing an obvious Mathematica command here that does this... Is there a way to do such a thing?

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marked as duplicate by Sjoerd C. de Vries, Michael E2, halirutan, Yves Klett, Artes Apr 9 '13 at 16:26

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You can use Symbol["a" <> ToString[#]] & /@ Range[20]. –  b.gatessucks Apr 9 '13 at 12:49
    
Thanks, that exactly the line that I needed! (except that I used Range[0,20] as I start at 0, but never mind that) –  Jelle Apr 9 '13 at 13:16
    
Other possible duplicates: this –  Sjoerd C. de Vries Apr 9 '13 at 13:38

1 Answer 1

up vote 3 down vote accepted

Depending on the problem you are having, it is maybe enough when you create a list of {a[0], a[1], a[2], a[3], ...}. This can be done with

Array[a, 10]

or, if you like Table

Table[a[i], {i, 10}]

If you really want to create an where n is a number, then you can use Symbol to convert a string to a symbol

Table[Symbol["a" <> ToString[i]], {i, 10}]

or, if you want definitely unassigned variables and you don't care which numbers they get

Table[Unique["a"], {10}]
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Ah, thank you very much! The Symbol[] command was just what I needed! –  Jelle Apr 9 '13 at 13:13
    
What about also mentioning ToExpression? –  Yves Klett Apr 9 '13 at 14:19
    
@YvesKlett I assume it will be closed as dup soon and in the other post ToExpression is used. –  halirutan Apr 9 '13 at 15:30
    
Yup. I voted for that but I think your answer is nice, short and useful anyway. –  Yves Klett Apr 9 '13 at 15:57

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