search string with array of values with 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?

use a break 2; when you find the first occurrence php.net/manual/en/control-structures.break.php — s3v3n
– s3v3n, Commented Dec 28, 2010 at 16:28
actually is the problem that you don't want to loop the entire array or that you can't pass an array as a needle? — s3v3n
– s3v3n, Commented Dec 28, 2010 at 16:38
I don't want to loop through the array, and I can't pass the needle as an array to strstr() — Patrick
– Patrick, Commented Dec 28, 2010 at 16:40

Michael Myers · Accepted Answer · 2012-06-13 15:02:45Z

7

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.

edited Jun 13, 2012 at 15:02

Michael Myers♦

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answered Dec 28, 2010 at 16:31

Felix Kling

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3 Comments

s3v3n Over a year ago

why to use regex if it is possible to simply use strstr() or in_array() ? it will increase the complexity of algorithm.

Felix Kling Over a year ago

@s3v3n: Yes you can loop and use strstr() and break when you found it. That is another solution. But in_array only works if the name of the file is equal to a word contained in the array. I understood the question in the way that the filename can contain words in the array...

s3v3n Over a year ago

Actually I got an idea. I'll post it now as an answer.

OV Web Solutions · Accepted Answer · 2010-12-28 16:31:01Z

1

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

answered Dec 28, 2010 at 16:31

OV Web Solutions

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3 Comments

Patrick Over a year ago

I'm not trying to match the entire filename though, does in_array() work on partial strings as well?

OV Web Solutions Over a year ago

@Patrick, could you provide an example of the file names you're working with? It may be easier to apply a specific naming convention to your files in order to get in_array() to work correctly. If you're goal is to not iterate through the array each time, in_array() is the best way to go.

Patrick Over a year ago

@OV Web Solutions, it will generally be file extension based, but I may have to do other conventions in the future.

s3v3n · Accepted Answer · 2010-12-28 16:53:29Z

1

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
}

answered Dec 28, 2010 at 16:53

s3v3n

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Comments

Joost · Accepted Answer · 2010-12-28 17:39:16Z

0

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)

edited Dec 28, 2010 at 17:39

answered Dec 28, 2010 at 16:39

Joost

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1 Comment

Joost Over a year ago

Well, let's say you have arrray('somevalue1', 'somevalue2') and the file value1. Using implode with :: would give somevalue1::somevalue2 and then strpos($imploded_array, 'value1') would return non-FALSE.

Jeroen Oomen · Accepted Answer · 2011-01-09 08:36:55Z

0

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; }

edited Jan 9, 2011 at 8:36

answered Jan 9, 2011 at 8:22

Jeroen Oomen

11 bronze badge

Comments

Uriel Acosta Hernández · Accepted Answer · 2017-03-29 23:17:09Z

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;
}

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