PHP substring extraction. Get the string before the first '/' or the whole string

Question

I am trying to extract a substring. I need some help with doing it in PHP.

Here are some sample strings I am working with and the results I need:

home/cat1/subcat2 => home

test/cat2 => test

startpage => startpage

I want to get the string till the first /, but if no / is present, get the whole string.

I tried,

substr($mystring, 0, strpos($mystring, '/'))

I think it says - get the position of / and then get the substring from position 0 to that position.

I don't know how to handle the case where there is no /, without making the statement too big.

Is there a way to handle that case also without making the PHP statement too complex?

Answer 1

The most efficient solution is the strtok function:

strtok($mystring, '/')

NOTE: In case of more than one character to split with the results may not meet your expectations e.g. strtok("somethingtosplit", "to") returns s because it is splitting by any single character from the second argument (in this case o is used).

@friek108 thanks for pointing that out in your comment.

For example:

$mystring = 'home/cat1/subcat2/';
$first = strtok($mystring, '/');
echo $first; // home

and

$mystring = 'home';
$first = strtok($mystring, '/');
echo $first; // home

Answer 2

Use explode()

$arr = explode("/", $string, 2);
$first = $arr[0];

In this case, I'm using the limit parameter to explode so that php won't scan the string any more than what's needed.

Answer 3

$first = explode("/", $string)[0];

Answer 4

What about this :

substr($mystring.'/', 0, strpos($mystring, '/'))

Simply add a '/' to the end of mystring so you can be sure there is at least one ;)

Answer 5

Late is better than never. php has a predefined function for that. here is that good way.

strstr

if you want to get the part before match just set before_needle (3rd parameter) to true http://php.net/manual/en/function.strstr.php

function not_strtok($string, $delimiter)
{    
    $buffer = strstr($string, $delimiter, true);

    if (false === $buffer) {
        return $string;
    }

    return $buffer;
}

var_dump(
    not_strtok('st/art/page', '/')
);

Answer 6

One-line version of the accepted answer:

$out=explode("/", $mystring, 2)[0];

Should work in php 5.4+

Answer 7

This is probably the shortest example that came to my mind:

list($first) = explode("/", $mystring);

1) list() will automatically assign string until "/" if delimiter is found
2) if delimiter "/"is not found then the whole string will be assigned

...and if you get really obsessed with performance, you may add extra parameter to explode explode("/", $mystring, 2) which limits maximum of the returned elements.

Answer 8

You can try using a regex like this:

$s = preg_replace('|/.*$|', '', $s);

sometimes, regex are slower though, so if performance is an issue, make sure to benchmark this properly and use an other alternative with substrings if it's more suitable for you.

Answer 9

The function strstr() in PHP 5.3 should do this job.. The third parameter however should be set to true..

But if you're not using 5.3, then the function below should work accurately:

function strbstr( $str, $char, $start=0 ){
    if ( isset($str[ $start ]) && $str[$start]!=$char ){
        return $str[$start].strbstr( $str, $char, $start+1 );
    }
}

I haven't tested it though, but this should work just fine.. And it's pretty fast as well

Answer 10

Using current on explode would ease the process.

 $str = current(explode("/", $str, 2));

Answer 11

You could create a helper function to take care of that:

/**
 * Return string before needle if it exists.
 *
 * @param string $str
 * @param mixed $needle
 * @return string
 */
function str_before($str, $needle)
{
    $pos = strpos($str, $needle);

    return ($pos !== false) ? substr($str, 0, $pos) : $str;
}

Here's a use case:

$sing = 'My name is Luka. I live on the second floor.';

echo str_before($sing, '.'); // My name is Luka

Answer 12

$arr = explode("/", $string, 2); $first = $arr[0];

This Way is better and more accurate than strtok because if you wanna get the values before @ for example while the there's no string before @ it will give you whats after the sign . but explode doesnt

Answer 13

why not use:

function getwhatiwant($s)
{
    $delimiter='/';
    $x=strstr($s,$delimiter,true);
    return ($x?$x:$s);
}

OR:

   function getwhatiwant($s)
   {
       $delimiter='/';
       $t=explode($delimiter, $s);
       return ($t[1]?$t[0]:$s);
   }

Answer 14

$string="kalion/home/public_html";

$newstring=( stristr($string,"/")==FALSE ) ? $string : substr($string,0,stripos($string,"/"));