Mathematica: If statment for lists

[Sarah rob]

I want to create an If statement that states; if the elements in, list1>0 , true subtract list2, false keep value from list1 so that i
end up with ans: {0,2,5,4}
list1 = {0, 2, 8, 9}
list2 = {1, 0, 3, 5}
I don't know how to represent the elements in the lists so that my If statement works

 

[Bill Simpson]

Excellent example showing input and output. That makes it much easier to provide correct help.

In[12]:=list1={0,2,8,9};list2={1,0,3,5};
f[x_,y_]:=If[x>0,x-y,x];
MapThread[f,{list1,list2}]

Out[15]={0,2,5,4}