InterpolatingFunction

InterpolatingFunction[domain, table] represents an approximate function whose values are found by interpolation.

Examples

Create from NDSolve:

sol = NDSolve[{y'[x] == y[x], y[0] == 1}, y, {x, 0, 1}];
ifun = y /. First[sol]
(* InterpolatingFunction[...] *)

Evaluate:

ifun[0.5]

Please visit the official Wolfram Language Reference for more details.