How to turn the string {'sin(30);'} into a command ,such as a = sin(30)=-0.9880 ?

There is a cell y = {'sin(30);'}, how can i get the 'sin(30)' as a command ,such as

    a = function(y) = sin(30) = -0.9880

Thank you!

Answer 1

[Azzi Abdelmalek]

 eval(y{1})

[Lisa Wu]

It is just what i want! Thank you very much!