php如何建一个数组

　　$arr=array(1,2,3,4);

$arr=array(
 　　　'name'=>'myj',
 　　　'age'=>'18',
 　　　'phone'=>'1888888888'
 　);

　$arr=array();

$a = 'aaa';
 $b = 'bbb';
 $c = 'ccc';
 $arr3 = compact('a','b','c');

{"a":"aaa","b":"bbb","c":"ccc"}

 $arr_key = array('a','b','c','d');
 $arr_val = array('1','2','3','4');
 echo var_dump(array_combine($arr_key,$arr_val));

 'a' => string '1' (length=1)
 'b' => string '2' (length=1)
 'c' => string '3' (length=1)
 'd' => string '4' (length=1)

$a=array_fill(2,3,"Dog");
print_r($a);

Array ( [2] => Dog [3] => Dog [4] => Dog )

 $arr = range(1,5); 输出：[1,2,3,4,5]
 $arr = range(1,15,3); 输出：1,4,7,10,13