I'm doing some heavy symbolic calculations and for preliminary simple tests I need to replace all coefficients except some choosings, e.g.:
A = {{0, 0}, {{2, 0}, {1, 1}, {0, 2}}, {{4, 0}, {3, 1}, {2, 2}, {1, 3}, {0, 4}}}
a = {{0, 0} -> e1, {1, 1} -> e2, {3, 1} -> e3} (* e.g from CoefficientRules *)
I want that something like A /. a gives {e1, {e2}, {e3}}.
These two similar question didn't help me:
I agree with Domen's answer. But if your coefficients were numeric and you were worried about the edge cases, you could do something like this:
Replace[A, Append[a, _ -> Nothing], {-2}]
I don't think it's worth complicating with some general except pattern. Since you know all your elements are in the form of {a_, b_}, just use this pattern to remove any numeric leftovers:
A /. a /. {_?NumberQ, _?NumberQ} -> Nothing
(* {e1, {e2}, {e3}} *)
may be (for the example you show)
A={{0,0},{{2,0},{1,1},{0,2}},{{4,0},{3,1},{2,2},{1,3},{0,4}}}
a={{0,0}->e1,{1,1}->e2,{3,1}->e3}
And now
Map[DeleteCases[#,_List]&,A/.a]
I am sure there are many other ways to do this. (AT least 9 more ways)
