# [Maxima] transforming a number to a list

reyssat eric.reyssat at math.unicaen.fr
Sun Jun 7 15:08:28 CDT 2009

```Gosse michel a écrit :
> Hello
>
> How can i transform a number to list of its digits :
> For instance, 345 -> [3,4,5]
>
Hello Michel
maybe this is what you want :
(%i1) f(x):=charlist(string(x));
(%o1)                     f(x) := charlist(string(x))
(%i2) f(345);   f(3^20);   f(-3^20);   f(3.1^10);
(%o2)                              [3, 4, 5]
(%o3)                   [3, 4, 8, 6, 7, 8, 4, 4, 0, 1]
(%o4)                  [-, 3, 4, 8, 6, 7, 8, 4, 4, 0, 1]
(%o5)         [8, 1, 9, 6, 2, ., 8, 2, 8, 6, 9, 8, 0, 8, 0, 1, 5]

If you don't want to get the sign or period then

%i6) g(x):=sublist(f(x),alphanumericp);
(%o6)                g(x) := sublist(f(x), alphanumericp)
(%i7) g(345);   g(3^20);   g(-3^20);   g(3.1^10);
(%o7)                              [3, 4, 5]
(%o8)                   [3, 4, 8, 6, 7, 8, 4, 4, 0, 1]
(%o9)                   [3, 4, 8, 6, 7, 8, 4, 4, 0, 1]
(%o10)         [8, 1, 9, 6, 2, 8, 2, 8, 6, 9, 8, 0, 8, 0, 1, 5]

nobody is perfect :
(%i11) g(3.1^50);
(%o11)   [3, 6, 9, 9, 0, 0, 3, 0, 6, 9, 6, 0, 7, 6, 1, 2, 2, E, 2, 4]
(and if you delete the E, it is even worse because mixes mantissa and
exponent !)

Eric
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>

```