Search an array for a matching string

Question

Hi There,

I am looking for away to check if a string exists as an array value in an array is that possible and how would I do it with PHP?

Answer 1

If you simply want to know if it exists, use in_array(), e.g.:

$exists = in_array("needle", $haystack);

If you want to know its corresponding key, use array_search(), e.g.:

$key = array_search("needle", $haystack);
// will return key for found value, or FALSE if not found

Answer 2

Php inArray()

Answer 3

Here you go:

http://www.php.net/manual/en/function.array-search.php

Answer 4

You can use PHP's in_array function to see if it exists, or array_search to see where it is.

Example:

$a = array('a'=>'dog', 'b'=>'fish');

in_array('dog', $a); //true
in_array('cat', $a); //false

array_search('dog', $a); //'a'
array_search('cat', $a); //false

Answer 5

The array_search function does exactly what you want.

$index = array_search("string to search for", $array);

Answer 6

Incidentally, although you probably should use either in_array or array_search like these fine gentlemen suggest, just so you know how to do a manual search in case you ever need to do one, you can also do this:

<?php

   // $arr is the array to be searched, $needle the string to find.
   // $found is true if the string is found, false otherwise.

   $found = false;
   foreach($arr as $key => $value) {
       if($value == $needle) {
           $found = true;
           break;
       }
   }

?>

I know it seems silly to do a manual search to find a string - and it is - but you may one day wish to do more complicated things with arrays, so it's good to know how to actually get at each $key-$value pair.

Answer 7

Say we have this array:

<?php
$array = array(
  1 => 'foo',
  2 => 'bar',
  3 => 'baz',
);
?>

If you want to check if the element 'foo' is in the array, you would do this

<?php
if(in_array('foo', $array)) {
  // in array...
}else{
  // not in array...
}
?>

If you want to get the array index of 'foo', you would do this:

<?php
$key = array_search('foo', $array);
?>

Also, a simple rule for the order of the arguments in these functions is: "needle, then haystack"; what you're looking for should be first, and what you're looking in second.