Originariamente inviato da LucianoS
non ho capito, scusa.
Ha un nome il costrutto o operatore tra le graffe?
Potrei scriverlo in altro modo?
Da: http://php.net/manual/en/language.types.string.php

String access and modification by character

Characters within strings may be accessed and modified by specifying the zero-based offset of the desired character after the string using square array brackets, as in $str[42]. Think of a string as an array of characters for this purpose. The functions substr() and substr_replace() can be used when you want to extract or replace more than 1 character.

Note: Strings may also be accessed using braces, as in $str{42}, for the same purpose.

La versione con le quadre e' di gran lunga piu' diffusa rispetto a quella con le graffe.