Make a matrix with a list : list2mat

### 2.37.38 Make a matrix with a list : `list2mat`

`list2mat` takes as argument a list `l` and an integer `p`.
`list2mat` returns a matrix having `p` column by cutting the list `l` in rows of length `p`. The matrix is filled with `0` if the size of `l` is not a multiple of `p`.
Input :

`list2mat([5,8,1,9,5,6],2)`

Output :

`[[5,8],[1,9],[5,6]]`

Input :

`list2mat([5,8,1,9],3)`

Output :

`[[5,8,1],[9,0,0]]`

Remark
`Xcas` displays matrix with [ and ] and lists with [ and ] as delimiters (the vertical bar of the brackets are thicker for matrices).