Get Help with Defining Functions in Mathematica

[Qyzren]

Hi, not sure where to put this, so i'll just put it here.
i was wondering if there is a way to define functions of this sort in mathematica.
For example.
f(x)=x if x>0 and f(x)=2x if x<=0.

I know you can break it up into 2 functions and go something like
g[x_]:=x;
h[x_]:=2x;
but those are 2 different functions with different domain ranges (0,Inf), (-Inf,0].
what i want is just 1 function in mathematica with domain (-Inf, Inf) that knows to use g if x>0, and h if x<=0 in my example.

Thank you.

*edit i figured it out,
PS how do i delete my post?

 

[Cyosis]

You can make use of the If statement.

f[x_]:=If[x>0,x,2x]