PHP, Structures and Functions of ARRAY


<?php

bool in_array ( mix $needle , arr $haystack [, bool $strict = FALSE ] )

where,

$needle = The value to be searched

$haystack = The array where the search will be performed

$strict = To control if the check is made over types or not

?>

$needle

The searched value.

If $needle is a STRING, the search is done by the case-sensitive manner.

$haystack

The array where the search will be performed.

$strict

To control if the check is made over types or not.

STRICT MODE
VALUES	PURPOSE
0 (FALSE)	TYPES WILL NOT BE CHECKED
1 (TRUE)	TYPES WILL BE CHECKED
ed48

EXERCISE


<?php

$haystack01 = [ 'THIRTY', 'forty', '88', 99 ];

$needle01 = 'thirty';
// lowercase

$tst01 = in_array($needle01, $haystack01);

if ($tst01 == true)
{
echo 'The needle: "' . $needle01 . 
           '"<br>WAS FOUND in haystack: <br>';
          print_r($haystack01);
}
else
{
echo 'The needle: "' . $needle01 . 
          '"<br>WAS NOT FOUND in haystack: <br>';
          print_r($haystack01);
}

?>

RESULT

The needle: "thirty"
WAS NOT FOUND in haystack:
Array ( [0] => THIRTY [1] => forty [2] => 88 [3] => 99 )

EXERCISE


<?php

$haystack02 = [ 'THIRTY', 'forty', '88', 99 ];

$needle02 = 'THIRTY';
// UPPERCASE

$tst02 = in_array($needle02, $haystack02);

if ($tst02 == true)
{
echo 'The needle: "' . $needle02 . 
           '"<br>WAS FOUND in haystack: <br>';
          print_r($haystack02);
}
else
{
echo 'The needle: "' . $needle02 . 
          '"<br>WAS NOT FOUND in haystack: <br>';
          print_r($haystack02);
}

?>

RESULT

The needle: "THIRTY"
WAS FOUND in haystack:
Array ( [0] => THIRTY [1] => forty [2] => 88 [3] => 99 )

EXERCISE


<?php

$haystack03 = [ 'THIRTY', 'forty', '88', 99 ];

$needle03 = '99';
// '99' STRING COMPARED TO 99 NUMBER

$tst03 = in_array($needle03, $haystack03, true);

if ($tst03 == true)
{
echo 'The needle: "' . $needle03 . 
           '" treated as STRING...<br>WAS FOUND in haystack: <br>';
          print_r($haystack03);
}
else
{
echo 'The needle: "' . $needle03 . 
          '" treated as STRING...<br>WAS NOT FOUND in haystack: <br>';
          print_r($haystack03); 
}

?>

RESULT

The needle: "99" treated as STRING...
WAS NOT FOUND in haystack:
Array ( [0] => THIRTY [1] => forty [2] => 88 [3] => 99 )

EXERCISE


<?php

$haystack04 = ['continents' => ['South America', 'Europe'], 
                        'countries' => ['Brasil', 'Portugal']];

$needle04 = ['Brasil', 'Portugal']; 

$tst04 = in_array($needle04, $haystack04, true);

if ($tst04 == true)
{
echo 'The needle:<br>';
var_export( $needle04 );
echo '<br>WAS found in the haystack:<br>';
print_r($haystack04);
}
else
{
echo 'The needle:<br>';
var_export( $needle04 );
echo '<br>WAS NOT found in the haystack:<br>';
print_r($haystack04);
}

?>

RESULT

The needle: array ( 0 => 'Brasil', 1 => 'Portugal', )
WAS NOT FOUND in haystack:
Array ( [continents] => Array ( [0] => South America [1] => Europe ) [countries] => Array ( [0] => Brasil [1] => Portugal ) )

EXERCISE


<?php

$haystack05 = ['continents' => ['South America', 'Europe'], 
                        'countries' => ['Brasil', 'Portugal']];

$needle05 = ['Brasil', 'Portugal']; 

$tst05 = in_array($needle05, $haystack05, false);

if ($tst05 == true)
{
echo 'The needle:<br>';
var_export( $needle05 );
echo '<br>WAS found in the haystack:<br>';
print_r($haystack05);
}
else
{
echo 'The needle:<br>';
var_export( $needle05 );
echo '<br>WAS NOT found in the haystack:<br>';
print_r($haystack05);
}


?>

EXERCISE


<?php

$haystack06 = 1234567;

$needle06 = 123; 

$tst06 = in_array($needle06, $haystack06, true);

if ($tst06 == true)
{
echo 'The needle:<br>';
var_export( $needle06 );
echo '<br>WAS found in the haystack:<br>';
print_r($haystack06);
}
else
{
echo 'The needle:<br>';
var_export( $needle06 );
echo '<br>WAS NOT found in the haystack:<br>';
print_r($haystack06);
} 

?>

RESULT

In PHP 7.4.XX it displays a Warning: ...,
in PHP 8.0.XX a Fatal error: ... will be issued.

Run this code to see these occurrences.