7.
定义域为\(R\)的偶函数\(r\left( x \right)\)满足\(r\left( x+1 \right)=r\left( x-1 \right)\),当\(x\in \left[ 0,1 \right]\)时,\(r\left( x \right)=x\);函数\(h\left( x \right)=\{\begin{matrix} {lo}{{{g}}_{3}}x,x > 0 \\ {{2}^{x}},x\leqslant 0 \\\end{matrix}\),则\(f\left( x \right)=r\left( x \right)-h\left( x \right),f\left( x \right)\)在\(\left[ -3,4 \right]\)上零点的个数为