# extracting digits in p-adic expansion

Here is a maybe naive question.

I am working over an unramified extansion of $\mathbb{Z}_p$ (let say of degree 2), say R.(c) = Zq(7^2) so that every element of R is written as ($a_0$ *c + $b_0$) + ($a_1$ *c + $b_1$) *7 + ($a_2$*c + $b_2$)*7^2 + $\ldots$ .

Is there a command to extract each of the $a_i$ or $b_i$ individually ?