$$f\left[ f\left( -1 \right) \right]=f\left[ {{\left( \frac{1}{4} \right)}^{-1}} \right]=f\left( 4 \right)={{\log }_{\frac{1}{2}}}4=-2$$ 
已知$$f(x)=\begin{cases}{{\left( \frac{1}{4} \right)}^{x}}, , x\in ( ,-\infty   ,  1  )   {{\log }_{\frac{1}{2}}}x,  x\in \left[  ,1  ,  +\infty \right) \end{cases}$$，则$$f\left[ f( ,-1) \right]=$$．

1: $$2$$ 
2: $$-2$$ 
3: $$\frac{1}{4}$$ 
4: $$-\frac{1}{2}$$ 