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What does the following code output:
<?php
$s = str_split("abcdefghijklmnopqrstuvwxyz", 2);
echo ($s[3][0]="e") ? $s[3][0].$s[2][0] : $s[1][0].$s[0][0];
?>
A: "ca"
B: "ge"
C: "ga"
D: "ee"
E: Notice: Cannot use object of type string as array in test.php on line 3
F: Fatal error: Call to undefined function str_split() in test.php on line 2
Answer
There's a str_split function and it splits a string using a given chunk size and returns the result as an array of strings, so that is not the problem.
You also can access the individual characters of a string using array indices so line 3 correct as far as syntax goes.
I hope you've noticed the bug on line 3. It's a very common mistake and very easy to overlook. In line 3 no comparison operator (==, ===, etc.) was used but an assignment operator. Therefore the expression $s[3][0]="e" assigns "e" to $s[3][0] and because "e" will evaluate to 'not false' the first part right after the question mark will be echoed to the browser. And because the original value "g" of $s[3][0] was overwritten by "e", "ee" will show up in your browser.
Here's a good lesson for you that can save you (and those who maintain your code) some headaches: In this situation where you compare a variable with some constant value swap the operands:
echo ("e"=$s[3][0]) ? ....
It looks weird but now you'll get an error and your typo will not cause a bug.
