Description
Import variables from an array into the current symbol table.
If flags is not specified, it is assumed to be EXTR_OVERWRITE.
EXTR_OVERWRITE
If there is a collision, overwrite the existing variable.
The danger is that any state variables set before the extract($_...)'s can be overwritten arbitrarily. This also makes it essential that any and every variable is instantiated prior to any use.
For more information on extract: http://www.php.net/extract