Splitting strings in PHP and get the last part

Question

I need to split a string in PHP by "-" and get the last part.

So from this:

abc-123-xyz-789

I expect to get

"789"

This is the code I've come up with:

substr(strrchr($urlId, '-'), 1)

which works fine, except:

If my input string does not contain any "-", I must get the whole string, like from:

123

I need to get back

123

and it needs to be as fast as possible.

Answer 1

• preg_split($pattern,$string) split strings within a given regex pattern
• explode($pattern,$string) split strings within a given pattern
• end($arr) get last array element

So:

$strArray = explode('-',$str)
$lastElement = end(explode('-', $strArray));
// or
$lastElement = end(preg_split('/-/', $str));

Will return the last element of a - separated string.

---

And there's a hardcore way to do this:

$str = '1-2-3-4-5';
echo substr($str, strrpos($str, '-') + 1);
//      |            '--- get the last position of '-' and add 1(if don't substr will get '-' too)
//      '----- get the last piece of string after the last occurrence of '-'

Answer 2

$string = 'abc-123-xyz-789';
$exploded = explode('-', $string);
echo end($exploded);

This does not have the E_STRICT issue.

Answer 3

Just check whether or not the delimiting character exists, and either split or don't:

if (strpos($potentiallyDelimitedString, '-') !== FALSE) {
  found delimiter, so split
}

Answer 4

To satisfy the requirement that "it needs to be as fast as possible" I ran a benchmark against some possible solutions. Each solution had to satisfy this set of test cases.

$cases = [
    'aaa-zzz'                     => 'zzz',
    'zzz'                         => 'zzz',
    '-zzz'                        => 'zzz',
    'aaa-'                        => '',
    ''                            => '',
    'aaa-bbb-ccc-ddd-eee-fff-zzz' => 'zzz',
];

Here are the solutions:

function test_substr($str, $delimiter = '-') {
    $idx = strrpos($str, $delimiter);
    return $idx === false ? $str : substr($str, $idx + 1);
}

function test_end_index($str, $delimiter = '-') {
    $arr = explode($delimiter, $str);
    return $arr[count($arr) - 1];
}

function test_end_explode($str, $delimiter = '-') {
    $arr = explode($delimiter, $str);
    return end($arr);
}

function test_end_preg_split($str, $pattern = '/-/') {
    $arr = preg_split($pattern, $str);
    return end($arr);
}

Here are the results after each solution was run against the test cases 1,000,000 times:

test_substr               : 1.706 sec
test_end_index            : 2.131 sec  +0.425 sec  +25%
test_end_explode          : 2.199 sec  +0.493 sec  +29%
test_end_preg_split       : 2.775 sec  +1.069 sec  +63%

So turns out the fastest of these was using substr with strpos. Note that in this solution we must check strpos for false so we can return the full string (catering for the zzz case).

Answer 5

array_reverse(explode('-', $str))[0]

Answer 6

This code will do that

<?php
$string = 'abc-123-xyz-789';
$output = explode("-",$string);
echo $output[count($output)-1];
?>

Answer 7

As per this post:

end((explode('-', $string)));

which won't cause an E_STRICT warning in PHP 5 (PHP magic). Although the warning will be issued in PHP 7, so adding @ in front of it can be used as a workaround.

Answer 8

As has been mentioned by others, if you don't assign the result of explode() to a variable, you get the message:

E_STRICT: Strict standards: Only variables should be passed by reference

The correct way is:

$words = explode('-', 'hello-world-123');
$id = array_pop($words); // 123
$slug = implode('-', $words); // hello-world

Answer 9

Since explode() returns an array, you can add square brackets directly to the end of that function, if you happen to know the position of the last array item.

$email = 'name@example.com';
$provider = explode('@', $email)[1];
echo $provider; // example.com

Or another way is list():

$email = 'name@example.com';
list($prefix, $provider) = explode('@', $email);
echo $provider; // example.com

If you don't know the position:

$path = 'one/two/three/four';
$dirs = explode('/', $path);
$last_dir = $dirs[count($dirs) - 1];
echo $last_dir; // four

Answer 10

The accepted answer has a bug in it where it still eats the first character of the input string if the delimiter is not found.

$str = '1-2-3-4-5';
echo substr($str, strrpos($str, '-') + 1);

Produces the expected result: 5

$str = '1-2-3-4-5';
echo substr($str, strrpos($str, ';') + 1);

Produces -2-3-4-5

$str = '1-2-3-4-5';
if (($pos = strrpos($str, ';')) !== false)
    echo substr($str, $pos + 1);
else
    echo $str;

Produces the whole string as desired.

3v4l link

Answer 11

This solution is null-safe and supports all PHP versions:

// https://www.php.net/manual/en/function.array-slice.php
$strLastStringToken = array_slice(explode('-',$str),-1,1)[0];

returning '' if $str = null.

Answer 12

The hardcore way for me:

  $last = explode('-',$urlId)[count(explode('-',$urlId))-1];

Answer 13

You can do it like this:

$str = "abc-123-xyz-789";
$last = array_pop( explode('-', $str) );
echo $last; //echoes 789

Answer 14

You can use array_pop combined with explode

Code:

$string = 'abc-123-xyz-789';
$output = array_pop(explode("-",$string));
echo $output;

DEMO: Click here

Answer 15

You can do it like this:

$str = "abc-123-xyz-789";
$arr = explode('-', $str);
$last = array_pop( $arr );
echo $last; //echoes 789

Answer 16

Just call the following single line of code:

 $expectedString = end(explode('-', $orignalString));