Using numbers as input in \newenvironment LaTeX

Question

I'm trying to make an environment that builds a column vector, and that takes as input the scale factor of the distancing between the rows:

\newenvironment{VEC}[1]{\begin{Bmatrix}\renewcommand{\arraystretch}{#1}}
                       {\end{Bmatrix}} 

I know that the \newenvironment command accepts as input only strings, so I tried with \value{#1} having no successfull result. Any help would be appreciated.

Answer 1

Nothing to do with newenvironment or arguments, you just need to switch the order:

\documentclass{article}
\usepackage{mathtools}

\newenvironment{VEC}[1]{\renewcommand{\arraystretch}{#1}\begin{Bmatrix}}
                       {\end{Bmatrix}} 


\begin{document}

\[
\begin{VEC}{3}
4\\
6\\
\end{VEC}
\]

\end{document}