> [] can be used on any variable, not just strings and arrays. It returns null and issues no warning.
It warns, will likely become an error in a later version (these are being slowly increased in error level to give people time to migrate): https://3v4l.org/qQdSP
> The [] indexing operator can also be spelled {}.
It warns, will likely become an error in a later version (these are being slowly increased in error level to give people time to migrate): https://3v4l.org/qQdSP
> The [] indexing operator can also be spelled {}.
Not anymore: https://3v4l.org/jtjCj
> Unlike (literally!) every other language with a similar operator, ?: is left associative. So this:
Not anymore: https://3v4l.org/t8io2
Regarding string/number comparisons:
https://wiki.php.net/rfc/string_to_number_comparison