为什么字符串在PHP 5.3中的行为类似于数组？

Question

I have this code:

$tierHosts['host'] = isset($host['name']) ? $host['name'] : $host;

It's working fine in PHP 5.5, but in PHP 5.3 the condition returns true while $host contains a string like pjba01. It returns the first letter of $tierHosts['host'], that is, p.

What's so wrong with my code?

Answer 1

You can access strings like an array and prior PHP 5.4 offsets like your name were silently casted to 0, means you accessed the first character of that string:

character | p | j | b | a | 0 | 1 |
-----------------------------------
index     | 0 | 1 | 2 | 3 | 4 | 5 |

After 5.3 such offsets will throw a notice, as you can also read in the manual:

As of PHP 5.4 string offsets have to either be integers or integer-like strings, otherwise a warning will be thrown. Previously an offset like "foo" was silently cast to 0.