passing parameters to functions

I have a function which has four parameters. I can pass variables to each of the four parameters by calling the function Example($parameter1=0,$parameter2=0,$parameter3=0,$parameter4=0); But if I assign the variable $temp, the concatenated string of the four parameters delimited with commas and then call the function as follows $temp=$parameter1.",".$parameter2.",".$parameter3.",".$parameter4; Example($temp); It ends up considering $temp as $parameter1 in the function, and then using default values for the other three parameters. How do I get the comma-delimited string to map to all four parameters? Ted Henigson Bonus question: In quoting strings, if I don't have to do any variable interpolation, does it matter whether I use single or double quotes?