"red","green"=>"green","white"=>"white","blue"=>"blue"); $colors["black"]="black"; $colors["red"]="#FF0000"; print_r($colors); echo "
"; if(isset($colors["green"])){ echo "我喜欢绿色。"; } echo "
"; unset($colors["green"]); if(!isset($colors["green"])){ echo "我又不喜欢绿色了。"; } echo "
"; echo gettype($colors["blue"]); echo "
"; var_dump($colors["blue"]); ?>