Defines a piecewise-defined expression from a list of
Piecewise[{{val1, cond1}, {val2, cond2}, …}]
Piecewise[{{val1, cond1}, …}, val]
Piecewise[{{1, x > 0}}] /. x -> 1
→ 1Piecewise[{{1/x, x != 0}}, 0] /. x -> 0
→ 0f = Interpolation[{{0, 0}, {1, 2}, {2, 0}}, InterpolationOrder -> 1]; g[w_] := Piecewise[{{f[w], 0 <= w <= 2}}, 0]; {g[1], g[5]}
→ {2, 0}