[php] How can I get the last 7 characters of a PHP string?

How would I go about grabbing the last 7 characters of the string below?

For example:

$dynamicstring = "2490slkj409slk5409els";
$newstring = some_function($dynamicstring);
echo "The new string is: " . $newstring;

Which would display:

The new string is: 5409els

It would be better to have a check before getting the string.

$newstring = substr($dynamicstring, -7);

if characters are greater then 7 return last 7 characters else return the provided string.

or do this if you need to return message or error if length is less then 7

$newstring = (strlen($dynamicstring)>7)?substr($dynamicstring, -7):"message";

substr documentation

For simplicity, if you do not want send a message, try this

$new_string = substr( $dynamicstring, -min( strlen( $dynamicstring ), 7 ) );

for last 7 characters

$newstring = substr($dynamicstring, -7);

$newstring : 5409els

for first 7 characters

$newstring = substr($dynamicstring, 0, 7);

$newstring : 2490slk

umh.. like that?

$newstring = substr($dynamicstring, -7);

Safer results for working with multibyte character codes, allways use mb_substr instead substr. Example for utf-8:

$str = 'Ne zaman seni düsünsem';
echo substr( $str, -7 ) . ' <strong>is not equal to</strong> ' .
  mb_substr( $str, -7, null, 'UTF-8') ;

last 7 characters of a string:

$rest = substr( "abcdefghijklmnop", -7); // returns "jklmnop"