# Z-transform of not quite an upsampler

I know the z-transform of an upsampler is:

$$y[n] = \begin{cases} x(n/L) &n=0,\pm L, \pm 2L, ...\\ 0&otherwise \end{cases} \longrightarrow Y(z)= X(z^{L})$$

if $$x[n]_L$$ is defined to zero for $$n <0$$ and $$n \ge L$$ and to be non-zero over interval $$[0, L-1]$$...then, what's the Z-transform of:

$$y[n] = \begin{cases} x[n]_L & 0 \le n \le L-1\\ 0&otherwise \end{cases} \longrightarrow Y(z) = ???$$

its kind of like:

$$y[n] = x[n]\ u[-n + L]\ u[n]$$

I have this z-transform for LPF that is similar, but doesn't match:

$$\begin{cases} y[n]=a^{n}&0 \le n \le L-1 \\ \\ 0& otherwise \end{cases} \longrightarrow Y(z) = \frac{1-a^Lz^{-L}}{1-a{\ z}^{-1}}$$

Ok, its a trick question...its $$Y(z) = X(z)$$ because $$y[n]$$ and $$x[n]_L$$ are identical sequences.
$$y[n] = \begin{cases} x[n]_L & 0 \le n \le L-1\\ 0&otherwise \end{cases} \longrightarrow Y(z) = X(z)$$