in_array

(PHP 4, PHP 5, PHP 7)

in_array — Checks if a value exists in an array

Description

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

Searches haystack for needle using loose comparison unless strict is set.

Parameters

needle: The searched value.

Note:
If needle is a string, the comparison is done in a case-sensitive manner.
haystack: The array.
strict: If the third parameter strict is set to TRUE then the in_array() function will also check the types of the needle in the haystack.

Return Values

Returns TRUE if needle is found in the array, FALSE otherwise.

Examples

Example #1 in_array() example


<?php
$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 program above will display:

Got Irix

Example #2 in_array() with strict example


<?php
$a = array('1.10', 12.4, 1.13);

if (in_array('12.4', $a, true)) {
    echo "'12.4' found with strict check\n";
}

if (in_array(1.13, $a, true)) {
    echo "1.13 found with strict check\n";
}
?>

The above example will output:

1.13 found with strict check

Example #3 in_array() with an array as needle


<?php
$a = array(array('p', 'h'), array('p', 'r'), 'o');

if (in_array(array('p', 'h'), $a)) {
    echo "'ph' was found\n";
}

if (in_array(array('f', 'i'), $a)) {
    echo "'fi' was found\n";
}

if (in_array('o', $a)) {
    echo "'o' was found\n";
}
?>

The above example will output:

  'ph' was found
  'o' was found

User Contributed Notes

beingmrkenny at gmail dot com

4 years ago


Loose checking returns some crazy, counter-intuitive results when used with certain arrays. It is completely correct behaviour, due to PHP's leniency on variable types, but in "real-life" is almost useless.

The solution is to use the strict checking option.

<?php

// Example array

$array = array(
    'egg' => true,
    'cheese' => false,
    'hair' => 765,
    'goblins' => null,
    'ogres' => 'no ogres allowed in this array'
);

// Loose checking -- return values are in comments

// First three make sense, last four do not

in_array(null, $array); // true
in_array(false, $array); // true
in_array(765, $array); // true
in_array(763, $array); // true
in_array('egg', $array); // true
in_array('hhh', $array); // true
in_array(array(), $array); // true

// Strict checking

in_array(null, $array, true); // true
in_array(false, $array, true); // true
in_array(765, $array, true); // true
in_array(763, $array, true); // false
in_array('egg', $array, true); // false
in_array('hhh', $array, true); // false
in_array(array(), $array, true); // false

?>

jv at vip dot ie

6 years ago


If you're working with very large 2 dimensional arrays (eg 20,000+ elements) it's much faster to do this...



<?php

$needle = 'test for this';



$flipped_haystack = array_flip($haystack);



if ( isset($flipped_haystack[$needle]) )

{

  print "Yes it's there!";

}

?>



I had a script that went from 30+ seconds down to 2 seconds (when hunting through a 50,000 element array 50,000 times).



Remember to only flip it once at the beginning of your code though!

Kelvin J

7 years ago


For a case-insensitive in_array(), you can use array_map() to avoid a foreach statement, e.g.:

<?php
    function in_arrayi($needle, $haystack) {
        return in_array(strtolower($needle), array_map('strtolower', $haystack));
    }
?>

bogdan AT bogdanconstantinescu DOT com

6 years ago


If you found yourself in need of a multidimensional array in_array like function you can use the one below. Works in a fair amount of time

<?php

    function in_multiarray($elem, $array)
    {
        $top = sizeof($array) - 1;
        $bottom = 0;
        while($bottom <= $top)
        {
            if($array[$bottom] == $elem)
                return true;
            else 
                if(is_array($array[$bottom]))
                    if(in_multiarray($elem, ($array[$bottom])))
                        return true;
                    
            $bottom++;
        }        
        return false;
    }
?>

crashrox at gmail dot com

7 years ago


Recursive in array using SPL



<?php

function in_array_recursive($needle, $haystack) {



    $it = new RecursiveIteratorIterator(new RecursiveArrayIterator($haystack));



    foreach($it AS $element) {

        if($element == $needle) {

            return true;

        }

    }



    return false;

}

?>

Lea Hayes

4 years ago


Determine whether an object field matches needle.



Usage Example:

---------------



<?php

$arr = array( new stdClass(), new stdClass() );

$arr[0]->colour = 'red';

$arr[1]->colour = 'green';

$arr[1]->state  = 'enabled';



if (in_array_field('red', 'colour', $arr))

   echo 'Item exists with colour red.';

if (in_array_field('magenta', 'colour', $arr))

   echo 'Item exists with colour magenta.';

if (in_array_field('enabled', 'state', $arr))

   echo 'Item exists with enabled state.';

?>



Output:

--------

Item exists with colour red.

Item exists with enabled state.



<?php

function in_array_field($needle, $needle_field, $haystack, $strict = false) {

    if ($strict) {

        foreach ($haystack as $item)

            if (isset($item->$needle_field) && $item->$needle_field === $needle)

                return true;

    }

    else {

        foreach ($haystack as $item)

            if (isset($item->$needle_field) && $item->$needle_field == $needle)

                return true;

    }

    return false;

}

?>

what loose checking means

2 years ago


In a high-voted example, an array is given that contains, amongst other things, true, false and null, against which various variables are tested using in_array and loose checking.

It impossible to receive false as a return value from in_array using loose checking if your arrays contains both the constants true and false. You might understandably trip over this (or the inverse - passing boolean true to check against an array of e.g. non-empty strings), but it's certainly not counter intuitive and makes perfect sense.

thomas dot sahlin at gmail dot com

6 years ago


If you're creating an array yourself and then using in_array to search it, consider setting the keys of the array and using isset instead since it's much faster.

<?php

$slow = array('apple', 'banana', 'orange');

if (in_array('banana', $slow))
    print('Found it!');

$fast = array('apple' => 'apple', 'banana' => 'banana', 'orange' => 'orange');

if (isset($fast['banana']))
    print('Found it!');

?>

Valerchik

2 years ago


Beware when using this function to validate user input:

$a = array('0' => 'Opt 1', '1' => 'Opt 2', '2' => 'Opt 3');
$v = 'sql injection';
var_dump(in_array($v, array_keys($a)));

This will result : true;

array_keys($a) will cast array keys to int instead of string !
then when in_array will compare it will cast  'sql injection' to int 0 !
Beware of this!

john at dwarven dot co dot uk

6 years ago


I just struggled for a while with this, although it may be obvious to others.

If you have an array with mixed type content such as:

<?php

 $ary = array (
   1,
   "John",
   0,
   "Foo",
   "Bar"
 );

?>

be sure to use the strict checking when searching for a string in the array, or it will match on the 0 int in that array and give a true for all values of needle that are strings strings.

<?php

var_dump( in_array( 2, $ary ) );

// outputs FALSE

var_dump( in_array( 'Not in there', $ary ) );

// outputs TRUE

var_dump( in_array( 'Not in there', $ary, TRUE ) );

// outputs FALSE

?>

rhill at xenu-directory dot net

7 years ago


I found out that in_array will *not* find an associative array within a haystack of associative arrays in strict mode if the keys were not generated in the *same order*:

<?php

$needle = array(
    'fruit'=>'banana', 'vegetable'=>'carrot'
    );

$haystack = array(
    array('vegetable'=>'carrot', 'fruit'=>'banana'),
    array('fruit'=>'apple', 'vegetable'=>'celery')
    );

echo in_array($needle, $haystack, true) ? 'true' : 'false';
// Output is 'false'

echo in_array($needle, $haystack) ? 'true' : 'false';
// Output is 'true'

?>

I had wrongly assumed the order of the items in an associative array were irrelevant, regardless of whether 'strict' is TRUE or FALSE: The order is irrelevant *only* if not in strict mode.

janis dot janovskis at gmail dot com

4 years ago


Since sometimes in_array returns strange results - see notes above.
I was able to find value in array by this quite a simple function;
<?php
/**
* $find <mixed> value to find
* $array<array> array to search in
*/

function _value_in_array($array, $find){
 $exists = FALSE;
 if(!is_array($array)){
   return;
}
foreach ($array as $key => $value) {
  if($find == $value){
       $exists = TRUE;
  }
}
  return $exists;
}

// Note
// You can't use wildcards and it does not check variable type
?>

rolf dot dergham dot public at gmail dot com

2 years ago


Watch out for this:

<?

print_r( (int) in_array('hello',array( 0 => 0)) );

?>

returns 1

Yes, it seems that is_array thinks that a random string and 0 are the same thing.
Excuse me, that's not loose checking, that's drunken logic.
Or maybe I found a bug?

tjamadeira at gmail dot com

3 months ago


This function is for search a needle in a multidimensional haystack:

<?php
/**
 * A special function for search in a multidimensional array a needle
 *
 * @param mixed needle The searched variable
 * @param array haystack The array where search
 * @param bool strict It is or it isn't a strict search?
 *
 * @return bool
 **/
function in_array_r($needle, $haystack, $strict = false){
 foreach($haystack as $item){
   if(is_array($item)){
     if(in_array_r($needle, $item, $strict)){
       return true;
     }
   }else{
     if(($strict ? $needle === $item : $needle == $item)){
       return true;
     }
   }
 }
 return false;
}
?>

dazero0 dot ls at gmail dot com

7 months ago


I would like to add something to beingmrkenny at gmail dot com comparison post. After debugging a system, i discovered a security issue in our system and his post helped me find the problem.

In my additional testing i found out that not matter what you search for in an array, except for 0 and null, you get true as the result if the array contains true as the value.

Examples as php code :

<?php
$a = ['a', 32, true, 'x' => y];
var_dump(in_array(25, $a)); // true, one would expect false
var_dump(in_array('ggg', $a)); // true, one would expect false

var_dump(in_array(0, $a)); // false
var_dump(in_array(null, $a)); // false
?> 

Such the best practice in our case is to use strict mode. Which was not so obvious.

splogamurugan at gmail dot com

5 months ago


var_dump(in_array('invalid', array(0,10,20))); 
The above code gives true since the 'invalid' is getting converted to 0 and checked against the array(0,10,20)

but var_dump(in_array('invalid', array(10,20)));  gives 'false' since 0 not there in the array

i dot pinz1 at gmail dot com

1 year ago


I have noted some strange behavior of the in_array() function if you have a hash like
$haystack=array (
'123'=>'some value',
'0125'=>'some value');

If I test now:
if (in_array('23',$haystack)) // here also TRUE is returned

I switched instead to 
if(isset($haystack['23'])) // which return correct FALSE

Maybe this helps others too.

Anonymous

4 years ago


known issue
when checking a string vs a integer

$testarray = array(0,1,2,3,4);

in_array("bla", $a) returns true
in_array("bla6", $a) returns true
in_array("6bla", $a) returns false 

"bla" as a integer value returns the number zero
"bla6" as a integer value returns the number zero
 "6bla" returns the number six as its the only vaild part of that

if you checking for unknown types eg string vs integer 
then you would need the strict value to be true.

ctulek at gmail dot com

5 years ago


If you have an array like:
$arr = array(0,1,2,3,4,5);

in_array(NULL, $arr) returns true because you have 0 in your array. That is, in_array does not use === for equal check.

Martijn Wieringa

7 years ago


When using numbers as needle, it gets tricky:

Note this behaviour (3rd statement):

in_array(0, array(42)) = FALSE
in_array(0, array('42')) = FALSE
in_array(0, array('Foo')) = TRUE
in_array('0', array('Foo')) = FALSE

musik at krapplack dot de

9 years ago


I needed a version of in_array() that supports wildcards in the haystack. Here it is:

<?php
function my_inArray($needle, $haystack) {
    # this function allows wildcards in the array to be searched
    foreach ($haystack as $value) {
        if (true === fnmatch($value, $needle)) {
            return true;
        }
    }
    return false;
}

$haystack = array('*krapplack.de');
$needle = 'www.krapplack.de';

echo my_inArray($needle, $haystack); # outputs "true"
?>

Unfortunately, fnmatch() is not available on Windows or other non-POSIX compliant systems.

Cheers,
Thomas

rick at fawo dot nl

10 years ago


Here's another deep_in_array function, but this one has a case-insensitive option :)
<?
function deep_in_array($value, $array, $case_insensitive = false){
    foreach($array as $item){
        if(is_array($item)) $ret = deep_in_array($value, $item, $case_insensitive);
        else $ret = ($case_insensitive) ? strtolower($item)==$value : $item==$value;
        if($ret)return $ret;
    }
    return false;
}
?>

kitchin

10 years ago


Here's a gotcha, and another reason to always use strict with this function.

$x= array('this');
$test= in_array(0, $x);
var_dump($test); // true

$x= array(0);
$test= in_array('that', $x);
var_dump($test); // true

$x= array('0');
$test= in_array('that', $x);
var_dump($test); // false

It's hard to think of a reason to use this function *without* strict.

This is important for validating user input from a set of allowed values, such as from a <select> tag.

adrian foeder

10 years ago


hope this function may be useful to you, it checks an array recursively (if an array has sub-array-levels) and also the keys, if wanted:

<?php
function rec_in_array($needle, $haystack, $alsokeys=false)
    {
        if(!is_array($haystack)) return false;
        if(in_array($needle, $haystack) || ($alsokeys && in_array($needle, array_keys($haystack)) )) return true;
        else {
            foreach($haystack AS $element) {
                $ret = rec_in_array($needle, $element, $alsokeys);
            }
        }
        
        return $ret;
    }
?>

rajeevroy15 at gmail dot com dot com

4 years ago


is_array function checks only array only and giving incorrect result with multi-dimensional arrays. 

Here is a custom function which will give the solution to check Array or Object and Checking of multi-dimensional arrays and objects as well. 

<?php 

function in_object($val, $obj){

    if($val == ""){
        trigger_error("in_object expects parameter 1 must not empty", E_USER_WARNING);
        return false;
    }
    if(!is_object($obj)){
        $obj = (object)$obj;
    }

    foreach($obj as $key => $value){
        if(!is_object($value) && !is_array($value)){
            if($value == $val){
                return true;
            }
        }else{
            return in_object($val, $value);
        }
    }
    return false;
}
?>
Usage  : 
<?php 

$array = array("a", "b", "c"=>array("x", "y"=>array("p", "q"=>"r")));

if(in_object("r", $arrX)){
    echo "r is there ";
}else{
    echo "Its not there ";
}
?>

sick949 at hotmail dot com

8 years ago


A first idea for a function that checks if a text is in a specific column of an array.
It does not use in_array function because it doesn't check via columns.
Its a test, could be much better. Do not use it without test.

<?php

function in_array_column($text, $column, $array)
{
    if (!empty($array) && is_array($array))
    {
        for ($i=0; $i < count($array); $i++)
        {
            if ($array[$i][$column]==$text || strcmp($array[$i][$column],$text)==0) return true;
        }
    }
    return false;
}

?>

Fabian S

2 years ago


Robin's fast_in_array uses binary search, so the array has to be sorted before, using the regular sort function.

santi dot morel at gmail dot com

2 years ago


search in multidimensional array

    function in_multiarray($elem, $array) {
        foreach ($array as $key => $value) {
            if ($value==$elem){
                return true;
            }
            elseif(is_array($value)){
                if($this->in_multiarray($elem, $value))
                        return true;
            }
        }
        
        return false;
    }

info at b1g dot de

8 years ago


Be careful with checking for "zero" in arrays when you are not in strict mode.
in_array(0, array()) == true
in_array(0, array(), true) == false

sandrejev at gmail dot com

10 years ago


Sorry, that deep_in_array() was a bit broken.



<?php

function deep_in_array($value, $array) { 

    foreach($array as $item) { 

        if(!is_array($item)) {

            if ($item == $value) return true;

            else continue; 

        }

        

        if(in_array($value, $item)) return true; 

        else if(deep_in_array($value, $item)) return true; 

    } 

    return false; 

}

?>

justinjohnmathews at gmail dot com

3 years ago


I think, "in_array" can be used with "range" function to check a number(dynamic value) is in between of other two numbers.

<?php 
    $i = 5; // Dynamic value    
    if (in_array(range(1, 10), $i)) {
       echo 'Your number is in between of range array';
    } 
?>

manuel at sunred dot org

2 years ago


If you are looking for a faster in_array function but still need the strict feature with which the type of element will be considered the following simple function might help you.

<?php
function fast_in_array($needle, array $haystack, $strict = false)
{
    $c = count($haystack);
    if($strict !== true)
    {
        for($i = 0; $i < $c; $i++)
            if($haystack[$i] == $needle)
                return true;
    }
    else
    {
        for($i = 0; $i < $c; $i++)
            if($haystack[$i] === $needle)
                return true;
    }
    return false;
}
?>

jordigirones at gmail dot com

7 years ago


function similar to in_array but implements LIKE '<string>%'



<?php

   function in_array_like($referencia,$array){

      foreach($array as $ref){

        if (strstr($referencia,$ref)){          

          return true;

        }

      }

      return false;

    }

?>

Aragorn5551 at gmx dot de

10 years ago


If you have a multidimensional array filled only with Boolean values like me, you need to use 'strict', otherwise in_array() will return an unexpected result.



Example:



<?php

$error_arr = array('error_one' => FALSE, 'error_two' => FALSE, array('error_three' => FALSE, 'error_four' => FALSE));



if (in_array (TRUE, $error_arr)) { 

   echo 'An error occurred';

}

else {

   echo 'No error occurred';

}

?>



This will return 'An error occurred' although theres no TRUE value inside the array in any dimension. With 'strict' the function will return the correct result 'No error occurred'.



Hope this helps somebody, cause it took me some time to figure this out.

user at NOSPAM at fullservicead dot com

5 years ago


After reading all other notes about performance, 
I made a little test. 

fill an array in a loop with random characters, 
shuffle it 
search on it using 4 methods.

I tried to have haystack as array and string; hence the strstr.

I tried it on 9, 99, 999, 9999 elements and the results
remain in the same order: 

9999 elements

Function :  execution time in miliseconds. 

strstr : 1.2994079589844
fast_in_array : 1.0655579566956
isset : 0.99128198623657 //Winner, used from another note here.
in_array : 2.9410798549652 

One last detail, I moved my functions around in the script to make sure there was no memory caching, reiteration op or whatever, it's all the same. in_array is the slowest and the use of isset($array[$NEEDLE]) the fastest.

I hope it saves somebody else the trouble.

Ray dot Paseur at Gmail dot com

4 years ago


Be VERY careful about testing for strings in arrays that might also contain integers.  In this snippet, the range() function turns the numeric values into integers, and loose data typing finds a match with zero.



Outputs:

PHP in_array() FOUND @#%?!! 

@#%?!! == 0 AT POSITION 26 BECAUSE OF LOOSE TYPE



<?php // RAY_temp_in_array.php

error_reporting(E_ALL);

echo "<pre>";



// THE ALLOWABLE SELECTIONS

$alpha = range('A','Z');

$alpha = array_merge($alpha, range('0', '9'));



// LOOK FOR A BOGUS SELECTION

$str = '@#%?!!';

if (in_array($str, $alpha))

{

    echo "PHP in_array() FOUND $str ";

}

else

{

    echo "$str IS NOT IN ARRAY";

}



// SEARCH THE ARRAY FOR THE KEY OF THE STRING

$key = array_search($str, $alpha);

echo "<br/>$str == $alpha[$key] AT POSITION $key";



if ($str == 0) echo " BECAUSE OF LOOSE TYPE";

?>

Kris Spencer

10 months ago


if using in_array to evaluate a boolean in a _GET or _POST, be sure to put single quotes around your "haystack values" or you will get a false result.

example of false/incorrect result:
[whatever.php?var=1 -- $_GET['var'] is 1]

if(!in_array($_GET['var'], array(0, 1), true)){
    echo 'not in array';
}
else{
    echo 'is in array';
}

output is "not in array" even though 1 === 1. Same is true without strict evaluation.

example of correct evaluation/result:
[whatever.php?var=1 -- $_GET['var'] is 1]

if(!in_array($_GET['var'], array('0', '1'), true)){
    echo 'not in array';
}
else{
    echo 'is in array';
}

output is now correct; "is in array".

natan dot volkovich at gmail dot com

6 years ago


If you're trying to find out whether or not at least a single value of an array matches a value in your haystack then use "array_intersect" instead of "in_array".



<?php

$needle = array(1,2);

$haystack = array(0,1,2);



echo "in_array: ".(int)in_array($needle, $haystack); // returns 0

echo "array_intersect: ".(int)array_intersect((array)$needle, $haystack); // returns 1

?>

Thingmand

7 years ago


A little function to use an array of needles:



<?php

function array_in_array($needles, $haystack) {



    foreach ($needles as $needle) {



        if ( in_array($needle, $haystack) ) {

            return true;

        }

    }



    return false;

}

?>

Joris Meijer

5 years ago


A good option if your array contains objects and you wish to recursively search it (eg. with in_arrayr), is to use json_encode and json_decode first:

<?php

$array = json_decode(json_encode($array_with_objects), true);

?>

In my opinion this is more elegant than a recursive in_array function which converts the objects into arrays while searching for a key and/or value.

Quaquaversal

8 years ago


A simple function to type less when wanting to check if any one of many values is in a single array.

<?php
function array_in_array($needle, $haystack) {
    //Make sure $needle is an array for foreach
    if(!is_array($needle)) $needle = array($needle);
    //For each value in $needle, return TRUE if in $haystack
    foreach($needle as $pin)
        if(in_array($pin, $haystack)) return TRUE;
    //Return FALSE if none of the values from $needle are found in $haystack
    return FALSE;
}
?>

Svinto

5 years ago


in_array() will always return true if a value in the haystack is of type bool(true).
This always hold except when the needle is of type bool(false).

Code:
<?php 
$haystack = array(true);
$needle = "anything except bool(false)";
$result = in_array($needle, $haystack);
var_dump($result); #Will always be true
?>

Solution:
run in_array() with strict set to true.
<?php
in_array($needle, $haystack, true);
?>

Tested on PHP 5.2.6

selmand [at] gmail.com

7 years ago


Removes same text with in_array in a string.

<?

$hizmet="aeg,akai,aeg,arcelik,aeg,arcelik,klima,kombi";

// alots of same stings

$x=explode(",",$hizmet);

$t= array();
$k=0;
for($i=0;$i<sizeof($x);$i++){ // this for remove its
    //echo $x[$i]."\n";
    if(!in_array($x[$i],$t))
    {
        $t[$k]=$x[$i];
        $k++;
    }
    
}

for($i=0;$i<sizeof($t);$i++){ // rebuilding $hizmet strings.
    
    echo $t[$i].",";
    
}

?>

brouwer dot p at gmail dot com

7 years ago


If made a in_array function that checks if the specified key matches. It works recursivly so it doesn't matter how deep your input array is.
<?php
  function myInArray($array, $value, $key){
    //loop through the array
    foreach ($array as $val) {
      //if $val is an array cal myInArray again with $val as array input
      if(is_array($val)){
        if(myInArray($val,$value,$key))
          return true;
      }
      //else check if the given key has $value as value
      else{
        if($array[$key]==$value)
          return true;
      }
    }
    return false;
  }
?>

bosdilooda at gmail dot com

5 years ago


There should be a big red warning sign here because this function behaves in mysterious ways...

let haystack be an array of integers:

$arr = array(1,2,3,4,5);

let $needle be a string of "2foobar"

then

in_array($needle,$arr)

will return true because string ("2foobar") evaluates to integer (2).

chris at axxis dot gr

4 years ago


It's funny how PHP has an in_array method, but not an in_object one. Here is a simple function which will check if a value can be found within an object.

<?php
  // in_object method
  // to check if a value in an object exists.
  function in_object($value,$object) {
    if (is_object($object)) {
      foreach($object as $key => $item) {
        if ($value==$item) return $key;
      }
    }
    return false;
  }
?>
  
This is very useful if an object has been created dynamically (especially from external code, which you don't control, as in an application-plugin, CMS, etc), and you don't know the object's properties. 
The above function will return the property, so you will be able to use it in your code later on.

Here is a very good basic example of how useful this function is!

<?php
  class My_Class {
    function __construct($key, $value) {
      $this->$key = $value;
      // As you can see, this is a dynamic class, its properties and values can be unknown...
    }
  }

  function in_object($value,$object) {
    if (is_object($object)) {
      foreach($object as $key => $item) {
        if ($value==$item) return $key;
      }
    }
    return false;
  }
  
  function manipulate_property($value,$object) {
    if ($property = in_object($value,$object)) {
      // value found. I can now use this property.
      // I can simply echo'it (makes no sense, as I could instead simply echo "value")
      echo "<br />I found the property holding this value: ".$object->$property; 
      // or (here comes the good part)
      // change the property
      $object->$property = "This is a changed value!";
      echo "<br />I changed the value to: ".$object->$property; 
      // or return it for use in my program flow
      return $property;
    } else {
      echo "Value NOT FOUND!<br />";
      return false;
    }
  }
  
  // imagine if some function creates the class conditionally...
  if ( 1 == 1) {
    $class = new My_Class("property","Unchanged Value");
  } else {
    $class = new My_Class("property","Some Other Value");
  }
  
  // now let's check if the value we want exists, and if yes, let's have some fun with it...
  $property = manipulate_property("Unchanged Value",$class);
  if ($property) {
    $my_variable = $class->$property;
    echo "<br />This is my variable now:".$my_variable; 
  } else $my_variable = $some_other_variable;
?>

Just run it to see for yourself!

robin at robinnixon dot com

6 years ago


This function is five times faster than in_array(). It uses a binary search and should be able to be used as a direct replacement:



<?php

function fast_in_array($elem, $array)

{

   $top = sizeof($array) -1;

   $bot = 0;



   while($top >= $bot)

   {

      $p = floor(($top + $bot) / 2);

      if ($array[$p] < $elem) $bot = $p + 1;

      elseif ($array[$p] > $elem) $top = $p - 1;

      else return TRUE;

   }

     

   return FALSE;

}

?>

Harry Willis

1 year ago


Kelvin's case-insensitive in_arrayi is fine if you desire loose typing, but mapping strtolower onto the array will (attempt to) cast all array members to string. If you have an array of mixed types, and you wish to preserve the typing, the following will work:

<?php
function in_array_ci($needle, array $haystack, $strict = false) {
    foreach ($haystack as $element) {
        if (gettype($needle) == 'string' && gettype($element) == 'string') {
            if (!strcasecmp($needle, $element)) {
                return true;
            }
        }
        elseif ($strict) {
            if ($needle === $element) {
                return true;
            }
        }
        else {
            if ($needle == $element) {
                return true;
            }
        }
    }

    return false;
}
?>

Chaya Cooper

1 year ago


To identify all instances of $needle when both $needle and $haystack are arrays, combine in_array() with a loop through the array  of needles.

I've posted a functional example of it here: http://sandbox.onlinephpfunctions.com/code/930385800c30595129cefb87cfa7eec9d69dce08

$needles = array('John', 'Alex');
$haystack = array('John','Alexander','Kim', 'Michael');

    foreach ($needles as $needle) {
        // Displays var name & value currently searching for) 
        echo '$needle: '.$needle;
        if (in_array($needle, $haystack) ) {
            echo ', True; ';
        }
       else {
            echo ', False; ';
        }
    }

Result is:
$needle: John, True; $needle: Alex, False;

Chaya Cooper

1 year ago


To identify all instances of $needle when both $needle and $haystack are arrays, combine in_array() with a loop through the array  of needles.

I've posted a functional example of it here: http://sandbox.onlinephpfunctions.com/code/930385800c30595129cefb87cfa7eec9d69dce08

$needles = array('John', 'Alex');
$haystack = array('John','Alexander','Kim', 'Michael');

    foreach ($needles as $needle) {
        // Displays var name & value currently searching for) 
        echo '$needle: '.$needle;
        if (in_array($needle, $haystack) ) {
            echo ', True; ';
        }
       else {
            echo ', False; ';
        }
    }

Result is:
$needle: John, True; $needle: Alex, False;

Artur K

2 years ago


As an addition to beingmrkennys note:

<?php

var_dump(in_array('012', array('12'))); //returns true
var_dump(in_array('012', array('12'), true)); //returns false

?>

Seems like PHP is making some cast. So use the strict parameter.

soxred93 at gmail dot com

7 years ago


Here's a simple little function I wrote that is a case insensitive version of in_array():



<?php

    function in_arrayi( $needle, $haystack ) {

        $found = false;

        foreach( $haystack as $value ) {

            if( strtolower( $value ) == strtolower( $needle ) ) {

                $found = true;

            }

        }    

        return $found;

    }

?>

tom at orbittechservices dot com

13 years ago


I searched the general mailing list and found that in PHP versions before 4.2.0 needle was not allowed to be an array.



Here's how I solved it to check if a value is in_array to avoid duplicates;



<?php

$myArray = array(array('p', 'h'), array('p', 'r'));



$newValue = "q";

$newInsert = array('p','q');



$itBeInThere = 0;

foreach ($myArray as $currentValue) {

  if (in_array ($newValue, $currentValue)) {

    $itBeInThere = 1;

  }

if ($itBeInThere != 1) {

  array_unshift ($myArray, $newInsert);

}

?>

james dot ellis at gmail dot com

7 years ago


Be aware of oddities when dealing with 0 (zero) values in an array...

This script:
<?php
$array = array('testing',0,'name');
var_dump($array);
//this will return true
var_dump(in_array('foo', $array));
//this will return false
var_dump(in_array('foo', $array, TRUE));
?>

It seems in non strict mode, the 0 value in the array is evaluating to boolean FALSE and in_array returns TRUE. Use strict mode to work around this peculiarity.
This only seems to occur when there is an integer 0 in the array. A string '0' will return FALSE for the first test above (at least in 5.2.6).

james dot randell at hotmail dot co dot uk

7 years ago


Small method i built for my Array module, after looking through the manual I wanted a small compact way of making a wildcard search through an arrays values, and returning only those that it found.



<?php



    /**

     * Takes a needle and haystack (just like in_array()) and does a wildcard search on it's values.

     *

     * @param    string        $string        Needle to find

     * @param    array        $array        Haystack to look through

     * @result    array                    Returns the elements that the $string was found in

     */

    function find ($string, $array = array ())

    {        

        foreach ($array as $key => $value) {

            unset ($array[$key]);

            if (strpos($value, $string) !== false) {

                $array[$key] = $value;

            }

        }        

        return $array;

    }

?>

Anonymous

10 years ago


in_arrayr -- Checks if the value is in an array recursively



Description

bool in_array (mixed needle, array haystack)



<?php

function in_arrayr($needle, $haystack) {

        foreach ($haystack as $v) {

                if ($needle == $v) return true;

                elseif (is_array($v)) return in_arrayr($needle, $v);

        }

        return false;

}

// i think it works

?>

tjamadeira at gmail dot com

3 months ago


A recursive function for a search in a multidimensional array using the in_array PHP function.

<?php
/**
 * A special function for search in a multidimensional array a needle
 *
 * This function uses many times the in_array PHP function
 *  to search a needle in a multidimensional haystack.
 *
 * @param mixed needle The searched variable
 * @param array haystack The array where search
 * @param bool strict It is or it isn't a strict search?
 *
 * @return bool
 **/
function in_array_r($needle, $haystack, $strict = false){
  if(in_array(array(), $haystack, $strict)){
    foreach($haystack as $item){
      if(is_array($item)){
        return in_array_r($needle, $item, $strict);
      }else {
        return in_array($needle, $haystack, $strict);
      }
    }
  }else {
    return in_array($needle, $haystack, $strict);
  }
}
?>

guitar king

8 years ago


In PHP 4, the first argument seems not allowed to be an object. In PHP 5, also objects are allowed as $needle.

in_array

Description

Parameters

Return Values

Examples

See Also

User Contributed Notes