CoefficientRules

CoefficientRules[poly, {x1, x2, ...}] gives exponent vectors and coefficients for monomials in poly.

Examples

Get exponent-coefficient rules:

CoefficientRules[x^2 + 3x*y + y^2, {x, y}]
(* {{2, 0} -> 1, {1, 1} -> 3, {0, 2} -> 1} *)

Single variable:

CoefficientRules[2x^3 + 5x + 1, {x}]
(* {{3} -> 2, {1} -> 5, {0} -> 1} *)

Please visit the official Wolfram Language Reference for more details.