Instructions for using the php in_array function and instructions for what you need to pay attention to in_array

in_array
(PHP 4, PHP 5)

in_array — Check if a value exists in the array

Description

Copy codeThe code is as follows:

bool in_array ( mixed $needle , array $haystack [, bool $strict ] )

Search needle in haystack, if found, return TRUE, otherwise return FALSE.

If the value of the third parameter strict is TRUE, the in_array() function will also check whether the type of needle is the same as that in haystack.

Note: If needle is a string, the comparison is case-sensitive.

Note: Prior to PHP version 4.2.0, needle was not allowed to be an array.

Example #1 in_array() >$os = array("Mac", "NT", "Irix", "Linux");
if (in_array("Irix", $os)) {
echo "Got Irix"; } if (in_array("mac", $os)) { echo "Got mac"; }
?>

The second condition fails because in_array() is case-sensitive, so the above program is displayed as:
Got Irix

Example #2 in_array() strict type checking example

Copy code

The code is as follows:

$a = array('1.10', 12.4, 1.13);
if (in_array('12.4', $a, true)) { echo "'12.4' found with strict checkn"; } if (in_array (1.13, $a, true)) { echo "1.13 found with strict checkn";
}
?>

The above example will output:

1.13 found with strict check

Example #3 Use array as needle in_array()

Copy code

The code is as follows:

$a = array(array('p', 'h'), array('p', 'r'), 'o') ;
if (in_array(array('p', 'h'), $a)) { echo "'ph' was foundn"; } if (in_array( array('f', 'i'), $a)) { echo "'fi' was foundn";
}
if (in_array('o', $a)) {
echo "'o' was foundn";
}
?>

The above example will output:

'ph' was found
'o ' was found

Things to note:

If:

First declare an array as:

　$arr = array(
*
);

Then: 　in_array(0, $arr) == true

Puzzling!
{Weak language}

Solution:

in_array(strval(0), $arr, true))

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TechArticle

in_array (PHP 4, PHP 5) in_array — Check whether a certain value exists in the array. Instructions for copying the code are as follows: bool in_array ( mixed $needle , array $haystack [, bool $strict ] ) in h...

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Instructions for using the php in_array function and instructions for what you need to pay attention to in_array_PHP Tutorial