PHPマージ配列関数array_merge()

$array = array('a'=>'bb');
$array2 = array('b'=>'cc');
$array3 = array_merge($array,$array2);

Array ( [a] => bb [b] => cc )

$array = 1;//array('a'=>'bb');
$array2 = array('b'=>'cc');
$array3 = array_merge($array,$array2);
print_r( $array3 );

Warning: array_merge() [function.array-merge]: Argument #1 is not an array in E:test1.php on (www.jb51.net)line 4

$array = 1;//array('a'=>'bb');
$array2 = array('b'=>'cc');
$array3 = array_merge((array)$array,(array)$array2);
print_r( $array3 );
输出结果不报错了
Array ( [0] => 1 [b] => cc )

<?php$a1=array("a"=>"red","b"=>"green");$a2=array("c"=>"blue","b"=>"yellow");print_r(array_merge($a1,$a2));?>

array_merge(array1,array2,array3...)