1. $f(x)$ is a function defined on $\mathbf{R}$ that is odd, and its smallest positive period is 2. Then the value of $f(-1)$ is $\qquad$ .
1.0.

Since $f(x+2)=f(x)$, let $x=-1$, then we have $f(-1+2)=f(-1)$,

which means $f(1)=f(-1)=-f(1)$.
Therefore, $f(-1)=0$.