7. Given the sequence $\left\{x_{n}\right\}$ satisfies $x_{1}=1, x_{n+1}=\frac{\sqrt{3} x_{n}+1}{\sqrt{3}-x_{n}}$. Then $\sum_{i=1}^{2017}\left|x_{i}\right|=$
7. 3361

Analysis: $x_{1}=1, x_{2}=2+\sqrt{3}, x_{3}=-2-\sqrt{3}, x_{4}=-1, x_{5}=-2+\sqrt{3}, x_{6}=2-\sqrt{3}, x_{7}=1$, so this sequence is a cyclic sequence. $\sum_{i=1}^{2017}\left|x_{i}\right|=\frac{2016}{6} \times 10+1=3361$