search string with array of values with PHP - php

Question

I am trying to search a list of files and only perform work on the files that have names that contain a few values in an array. I am hoping to not have to loop through the array each time I have a new filename.
ala-
$needle = array('blah', 'bleh');
foreach($file_list as $file)
{
foreach($needle as $need)
if(strstr($file, $need) !== false)
{
// do something...
}
}
I just need to know if one of the strings in the array is in the filename, not the location of the string.
I would like to use something similar to strstr() but it does not allow an array to be used as the needle.
i.e.-
if(strstr($haystack, array('blah', 'bleh')))
{
// do something...
}
I would prefer to stay away from regular expressions, it seems to be a sledge for a hammer's job. any ideas?

Answer 1

IMO it is fine to use regular expressions here:
$pattern = '/' . implode('|', array_map('preg_quote', $needle)) . '/i';
foreach($file_list as $file) {
if(preg_match($pattern, $file)) {
// do something
}
}
Reference: preg_quote
Here is a more "creative" way to do it (but it uses internal loops and is very likely slower, as you actually loop several times over the array):
function cstrstr($haystack, $needle) {
return strstr($haystack, $needle) !== false;
}
foreach($file_list as $file) {
if(array_sum(array_map('cstrstr',
array_pad(array($file), count($needle), $file),
$needle))) {
// do something
}
}
But the advantages with the regex should be obvious: You have to create the pattern only once whereas in the "funny" solution you always have to create an array of length count($needle) for every $file.

Answer 2

Patrick,
You can use in_array(). Example:
foreach($file_list as $file){
if(in_array($file, $needle)){
//--------------
// Needle found
}
}
You can find more examples here: http://php.net/manual/en/function.in-array.php

Answer 3

This will perform an action on all the files that contain all the needles inside their name
// Loop through files
foreach($files as $file){
foreach($needles as $needle){
// if filename does not contain this needle
if(strpos($file, $needle) === false)
continue 2; // skip to next file
}
// this file matches criteria. do smth on this file
}

Answer 4

in_array may work just fine, however it would require exact matches in your needle array.
You could implode the array with some hash-string, and use the result with strstr or strpos —str variant returns the first occurrence, pos only the position of the first occurrence— Make sure to have a very unique string, with both an uncommon prefix and suffix. This is rather a quick and dirty approach, but it may just work in your situation.
EDIT I was just thinking, why don't you want to use a loop? It'll be much faster than concatenating all elements from an array. Your question if there is a function to find partial matches using a reference array: it's not build-in, so you'd better use your own loop (or implement some function to do it, using a loop of course)

Answer 5

if( strstr( implode( " ", $array ), $search ) { //found }
But a function with loop and return when found is faster and less memory consuming.
function searchArrayFast( $array, $search )
{
foreach ( $array as $a )
{
if( strstr( $a, $search)){
return true;
}
}
return false;
}

Answer 6

Do not use preg_match() if you only want to check if one string is contained in another string. Use strpos() instead as it will be faster.
http://php.net/manual/en/function.preg-match.php
$needle = array('blah', 'bleh');
foreach ($file_list as $file) {
$result = $this->searchStrpos($file, $needle);
if ($result !== false) {
// do something...
}
}
/**
*
* #param String $string String search
* #param mixed $needle
* #param Boolean $onlyFirst return true but
* #return Boolean Return boolean for search
*/
private function searchStrpos($string, $needle, $onlyFirst = true) {
if (is_array($needle)) {
foreach ($needle as $item) {
$result = strpos($string, $item);
if ($result !== false && $onlyFirst) {
break;
}
}
} else {
$result = strpos($string, $needle);
}
return $result;
}