Quickly simulate values and evaluate

Questions
,
1 
x = {{a + b, b*c}, {c + d, d + (a + c)}}
numx = RandomReal[{0, 1}, {Length[Variables[x]]}]
x /. {a -> numx[[1]], b -> numx[[2]], c -> numx[[3]], d -> numx[[4]]}

Is there a better (more efficient) way to do this?

2

The following keeps you from having to write out the set of rules in the final expression and so may be valuable for more complicated situations:

x = {{a + b, b*c}, {c + d, d + (a + c)}};

replacements = Thread [Variables[x] -> RandomReal[{0, 1}, {Length[Variables[x]]}]];

x /. replacements

--David
http://scientificarts.com

3

Just another way:

x = {{a + b, b*c}, {c + d, d + (a + c)}};
rep = # -> RandomReal[] & /@ Variables[x];
x /. rep