What should you pay attention to when using the list function in PHP?

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

Example:

<?php
$my_array = array("Dog","Cat","Horse");
list($a, $b, $c) = $my_array;
echo "I have several animals, a $a, a $b and a $c.";
?>

Output:

I have several animals, a Dog, a Cat and a Horse.

When using the list() function, you need to pay attention:

● list() actually It is a language structure, not a function.

● The list() function is only used in numerically indexed arrays

We can look at the my_array array in the above example:

<?php
$my_array = array("Dog","Cat","Horse");
var_dump($my_array);
?>

Output:

array (size=3)
  0 => string 'Dog' (length=3)
  1 => string 'Cat' (length=3)
  2 => string 'Horse' (length=5)

It can be seen that the index of the my_array array is a numeric index.

● Assuming that the numerical index starts from 0, that is, assigning values ​​to variables starting from index 0

If the corresponding numerical index does not exist, the variable in the corresponding bit will have a null value.

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