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php128 apg

REWINDS the internal ARRAY pointer.





This function behaves just like next, except it rewinds the internal array pointer one place instead of advancing it.

To test the returned value the operator === must be used.

This function may return also a non-Boolean value which is evaluated as FALSE.



<?php 

mix prev ( arr &$array )


where,

$array = The given input ARRAY

?>

 $array 


The given input array.

Can be passed by reference.



  1 EXERCISE   

<?php

$arr01b =  [ "first index" => "FIRST ELEMENT",
               "second index" => "SECOND ELEMENT", 
                  "third index" => "THIRD ELEMENT", 
                "fourth index" => "FOURTH ELEMENT", 
                  "fifth index" => "FIFITH ELEMENT", 
                 "sixth index" => "SIXTH ELEMENT" ];

echo 'The given ARRAY:<br>';  
print_r($arr01b);

echo '<br><br>The current INDEX:<br>'; 
$ndx01b = key($arr01b);
print_r($ndx01b);

echo '<br><br>The current ELEMENT:<br>'; 
$frs01b = current($arr01b);
print_r($frs01b);

$lst01b = end($arr01b);

echo '<br><br><br>The LAST INDEX:<br>'; 
$key01b = key($arr01b);
print_r($key01b);

echo '<br><br>The LAST ELEMENT:<br>'; 
print_r($lst01b);

$prev01b1 = prev($arr01b);

$prev01b2 = prev($arr01b);

echo '<br><br><br>Internal pointer moved back twice.
          <br>The current INDEX:<br>';
$key01b2 = key($arr01b);
print_r($key01b2);

echo '<br><br>Internal pointer moved back twice.
          <br>The current ELEMENT:<br>';
print_r($prev01b2);

?>

 RESULT   

The given ARRAY:
Array
(
[first index] => FIRST ELEMENT
[second index] => SECOND ELEMENT
[third index] => THIRD ELEMENT
[fourth index] => FOURTH ELEMENT
[fifth index] => FIFITH ELEMENT
[sixth index] => SIXTH ELEMENT
)

The current INDEX:
first index

The current ELEMENT:
FIRST ELEMENT


The LAST INDEX:
sixth index

The LAST ELEMENT:
SIXTH ELEMENT


Internal pointer moved back twice.
The current INDEX:
fourth index

Internal pointer moved back twice.
The current ELEMENT:
FOURTH ELEMENT

  2 EXERCISE   

<?php

$arr02b =  [];

echo 'The given ARRAY:<br>';  
print_r($arr02b);

echo '<br><br>The current INDEX:<br>'; 
$ndx02b = key($arr02b);
var_dump($ndx02b);

echo '<br><br>The current ELEMENT:<br>'; 
$frs02b = current($arr02b);
var_dump($frs02b);

$lst02b = end($arr02b);

echo '<br><br><br>The LAST INDEX:<br>'; 
$key02b = key($arr02b);
var_dump($key02b);

echo '<br><br>The LAST ELEMENT:<br>'; 
var_dump($lst02b);

$prev02b1 = prev($arr02b);

$prev02b2 = prev($arr02b);

echo '<br><br><br>Internal pointer moved back twice.
          <br>The current INDEX:<br>';
$key02b2 = key($arr02b);
var_dump($key02b2);

echo '<br><br>Internal pointer moved back twice.
          <br>The current ELEMENT:<br>';
var_dump($prev02b2);

?>

 RESULT   

The given ARRAY:
Array()

The current INDEX:
NULL

The current ELEMENT:
bool(false)


The LAST INDEX:
NULL

The LAST ELEMENT:
bool(false)


Internal pointer moved back twice.
The current INDEX:
NULL

Internal pointer moved back twice.
The current ELEMENT:
bool(false)