Didn't we have to consider that array element could be not a number?

In general, no it's not good practice to put everything on one line. In this case, it's fine. This is a very pythonic solution, this would be just fine as is in almost any codebase (depending on usecase).

is it good practice to put everything in one line? it's elegant, but may get hard to read, once things get complicated.

I had exactly the same solution!

:P

and then of course, there's this

biggest facepalm i ve ever had

Yes - recursions are fascinating, however, be careful with them. Recursions could be double-edged swords...
Consider that each recursion level costs in memory on the stack. So if you have too many levels (self invocation) you would end up with a crash on lack of memory (or slowing down your whole computer as your code exhausts whole of the available memory).
In this specific case it is probably fine - we assume a number with a reasonable number of digits.

Cara, gostei muito da sua solução.
Sinceramente me fez pensar em como eu ainda tenho que melhorar, porque a minha resposta teve algumas linhas a mais, mas isso só serve de incentivo para continuar evoluindo

WoW

Very simple to use ;)

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