Case function in Mathematica

omri3012

Does anyone familiar with a convenient way in Mathematica to define a case function such as:

[itex] y(x)=\left\{\begin{array}{c} x \\ -x\end{array}\begin{array}{c} x>0 \\ x<0\end{array}
\right. [/itex]
?

Thankes,
Omri

phyzguy

You want to use 'Piecewise':

y[x_]:=Piecewise[{{x,x>0},{-x,x<0}}]

omri3012

Thankes,
It's very helpful :)