extract() question

There is this array which I would like to convert into a series variables using the extract function: <? $oz = array( "lion" => "courage", "dorothy" => "kansas", "scarecrow" => "brain" "tin man" => "heart"); extract($oz); ?> now, I would like to access my new variables. it is obviously easy for $lion, $dorothy, and $scarecrow but it isn't for "tin man". from this, I have 3 or 4 questions: 1) has $oz["tin man"] been passed into a variable? 2) if yes, how do I access the variable that came out of $oz["tin man"]? 3) let's pretend that I have no control over the names of the keys for $oz, how should I have called extract() to tell it to replace the space between "tin" and "man" by a underscore character? 4) finally, is there a way to access and retrieve that values of the symbol table without knowing their names? David