  We show that partition functions of various matrix models can be obtained by
acting on elementary functions with exponents of W-operators. A number of
illustrations is given, including the Gaussian Hermitian matrix model,
Hermitian model in external field and the Hurwitz-Kontsevitch model, for which
we suggest an elegant matrix-model representation. In all these examples, the
relevant W-operators belong to the W_3-algebra.
