Running "strpos" on each array element

I need to find out if a string exists within an array value, but isn't necessarily the actual array value.

$array = array(
       0 => 'blue', 
       1 => 'red', 
       2 => 'green', 
       3 =&g开发者_运维知识库t; 'red'
);

$key = xxxxxx('gr', $array); // $key = 2;

Is there a built in way to do this with PHP

You can use preg_grep for this purpose

<?php
$array = array(
       0 => 'blue', 
       1 => 'red', 
       2 => 'green', 
       3 => 'red'
);

//$key = xxxxxx('gr', $array); // $key = 2;
$result=preg_grep("/^gr.*/", $array);
print_r($result);
?>

DEMO

Function: array_filter is what you want. It will only preserve the items in the resulting array when the specified function return true for them.

// return true if "gr"  found in $elem
// for this value
function isGr($key, $elem)
{
    if (strpos($elem, "gr") === FALSE)
    {
         return FALSE;
    }
    else
    {
         return TRUE;
    }
}

$grElems = array_filter($array, "isGr");
print_r($grElems);

results in:

array(
    2=>'green'
)

Your xxxxxx would be array_map. But alas, you cannot use strpos as plain callback here. To pass the actual search parameter, you need to define a custom or anonymous function-

And to get what you want, you need more wrapping still:

 $key = key(
          array_filter(
             array_map(
                function($s){return strpos($s, "gr");},
                $array
             ),
          "is_int")
        );

This gives you the searched index 2 however.

There is no built-in function but since preg_* functions support arrays as arguments this should work:

$keys = preg_filter('~gr~', '$0', $array);

what about foreach ?

function xxxxxx($str, $array) {
  foreach ($array as $key => $value) {
     if (strpos($value, $str) !== false) {
        return $key;
     }
  }
  return false;
}

use

array_walk with strpos

array_walk

Loop through the array and check each item, then return the index if it does.

function substr_in_array($array, $substr) {
    foreach ($array as $index => $item) {
        if (strrpos($item, $substr)!===FALSE && $item != $substr) {
            return $index;
        }
    }
}

This should do what you want.

It checks using foreach every array element using strpos.

<?php
$array = array(
       0 => 'blue', 
       1 => 'red', 
       2 => 'green', 
       3 => 'red'
);
$search='aaa';
function arraysearch($array,$search){
foreach ($array as $element){
if(strpos($element,$search)!==FALSE){
return TRUE;
}
}
return FALSE;
}
echo arraysearch($array,$search);
?>

With PHP 5.3 you can do it in one command using array_filter and an anonymous function:

$keys = array_filter($array, function($var){ return strpos($var, 'gr') !== false; });

By using PHP >= 5.3.0, you could use anonymous functions as callback to filter that array with array_filter.

$array = array(
    0 => 'blue', 
    1 => 'red', 
    2 => 'green', 
    3 => 'red'
);

$search = 'gr';

$key = array_filter($array, function($element) use($search) {
    return strpos($element,$search) !== FALSE;
});

This is an improved version of Shay Ben Moshe response.