PHP Language--arrays

1. Array definitions

defined in different ways

You can put any type of data inside the array.

1). Indexed array

$attr Array ("AA");
Print_r ($ATTR);

2). Associative arrays

$attr Array ("One" =>10, "one" and "a" = "AA", "three" =>20); // Key=>value Print_r ($attr); Echo $attr // associative arrays can only be taken with key

2. Iterating through an array

For loop traversal, can only traverse indexed array, cannot traverse associative array

$attr Array ("AA");  for ($i$i<count($attr); $i+ +)  {echo$attr[$i];}

foreach traversal, which can traverse associative arrays and indexed arrays

// traversing values only foreach ($attr as$value) {echo$value;} // traversing keys and values  for ($attras$key= +$value) {echo$key ." = ". $value ;}

each () function list () function

//each () function, go to an element inside the array, take the value down, and return the element as an array$attr=Array("One" =>10, "2" = "AA", "three" =>20);Print_r( each($attr));Print_r( each($attr));Print_r( each($attr));Echo"------------------------"Reset($attr);//pointer Reset, pointing to the first element

 // list () function   $attr  = array  (1,2,3,4, "AA" ); list  ( $a ,  $b ,  $c ) =  $attr   echo   $a   echo   $b   echo   $c   list  (,,,,  $f ) = $attr  

// each () and  list () iterates through an array, indexed arrays and associative arrays can be $attrArray ("One" =>10, "2" = "AA", "three" = >20);  while (list($key,$value) =each(attr)) {  echo$key ." = ". $value. " <br> ";}

3. Pointers

 Current($attr);//takes the current pointer to the contents of the valueKey($ATTT);//index key to which the current pointer is pointingNext($attr);//move the pointer downprev($attr);//move the pointer upEnd($attr);//point pointer to last elementReset($attr); Reset the pointer//Traverse Do{Echo  Key($attr);Echo  Current($attr);Echo"<br>";} while(Next($attr))

4. Pre-defined arrays

$_server   Server and execution Environment information $_get$_post$_request$_files$_cookie $_session

PHP Language--arrays