How to Explode String Right to Left?

Question

$split_point = \' - \';
$string = \'this is my - string - and more\';

How can i make a split using the second instance of $split_point and not the

Answer 1

You may use strrev to reverse the string, and then reverse the results back:

$split_point = ' - ';
$string = 'this is my - string - and more';

$result = array_map('strrev', explode($split_point, strrev($string)));

Not sure if this is the best solution though.

Answer 2

Just an idea:

function explode_reversed($delim,$s){
  $result = array();
  $w = "";
  $l = 0;
  for ($i = strlen($s)-1; $i>=0; $i-- ):
    if ( $s[$i] == "$delim" ):
      $l++;
      $w = "";
    else:
      $w = $s[$i].$w;
    endif;
    $result[$l] = $w;
  endfor;
return $result;
}
$arr = explode_reversed(" ","Hello! My name is John.");
print_r($arr);

Result:

Array
(
    [0] => John.
    [1] => is
    [2] => name
    [3] => My
    [4] => Hello!
)

But this is much slower then explode. A test made:

$start_time = microtime(true);
for ($i=0; $i<1000;$i++)   
  $arr = explode_reversed(" ","Hello! My name is John.");
$time_elapsed_secs = microtime(true) - $start_time;
echo "time: $time_elapsed_secs s<br>";

Takes 0.0625 - 0.078125s

But

for ($i=0; $i<1000;$i++)   
  $arr = explode(" ","Hello! My name is John.");

Takes just 0.015625s

The fastest solution seems to be:

array_reverse(explode($your_delimiter, $your_string));

In a loop of 1000 times this is the best time I can get 0.03125s.

Answer 3

$split_point = ' - ';
$string = 'this is my - string - and more';
$result = end(explode($split_point, $string));

This is working fine

Answer 4

Assuming you only want the first occurrence of $split_point to be ignored, this should work for you:

# retrieve first $split_point position
$first = strpos($string, $split_point);
# retrieve second $split_point positon
$second = strpos($string, $split_point, $first+strlen($split_point));
# extract from the second $split_point onwards (with $split_point)
$substr = substr($string, $second);

# explode $substr, first element should be empty
$array = explode($split_point, $substr);

# set first element as beginning of string to the second $split_point
$array[0] = substr_replace($string, '', strpos($string, $substr));

This will allow you to split on every occurrence of $split_point after (and including) the second occurrence of $split_point.

Answer 5

Here is another way of doing it:

$split_point = ' - ';
$string = 'this is my - string - and more';

$stringpos = strrpos($string, $split_point, -1);
$finalstr = substr($string,0,$stringpos);

Answer 6

If I understand correctly, you want the example case to give you ('this is my - string', 'and more')?

Built-in split/explode seems to be forwards-only - you'll probably have to implement it yourself with strrpos. (right-left search)

$idx = strrpos($string, $split_point);
$parts = array(substr($string, 0, $idx), substr($string, $idx+strlen($split_point)))