Example usage of list() function in php and how to assign values ​​in array to variables

PHP list() assigns the values ​​in the array to some variables in one step. Like array(), list() is not a true function, but a language construct.

Syntax:

void list( mixed var, mixed ... )

Note: list() can only be used on numerically indexed arrays and assumes that numerical indexing starts at 0.

The list() function in PHP is used to assign values ​​to a set of variables in one operation.

Like array(), this is not really a function, but a language construct. List() is used to specify one of the variables in the list Job.

Example:

<?php
$info = array(&#39;coffee&#39;, &#39;brown&#39;, &#39;caffeine&#39;);
// Listing all the variables
list($drink, $color, $power) = $info;
echo "$drink is $color and $power makes it special.n";
// Listing some of them
list($drink, , $power) = $info;
echo "$drink has $power.n";
// Or let&#39;s skip to only the third one
list( , , $power) = $info;
echo "I need $power!n";
// list() doesn&#39;t work with strings
list($bar) = "abcde";
var_dump($bar); // NULL
?>

Example 1:

<?php
$arr_age = array(18, 20, 25);
list($wang, $li, $zhang) = $arr_age;
echo $wang;    //输出：18
echo $zhang;    //输出：25
?>

Example 2, data table query:

$result = mysql_query("SELECT id, username, email FROM user",$conn);
while(list($id, $username, $email) = mysql_fetch_row($result)) {
  echo "用户名：$username<br />";
  echo "电子邮箱：$email";
}

list() using array index

list() allows the use of another array to receive the values ​​assigned by the array, but when using an index array, the order of assignment is opposite to the order listed in list():

$arr_age = array(18, 20, 25);
list($a[0], $a[1], $a[2]) = $arr_age;

print_r($a);The output $a array structure is as follows:

Array ( [2] => 25 [1] => 20 [0] => 18 )

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