Hi friends. Why does this code output 2 ??? I didn't understand?

Question

<?php
$var = true ? '1' : false ? '2' : '3';
echo $var;
?>
https://code.sololearn.com/wMd7Sx3SbsFu/?ref=app

Answer 1

Ipang , I agree with the rest, but I don't think the assignment operator gets precedence here. It's more like

$var = (((true) ? '1' : false) ? '2' : '3');
$var = (('1') ? '2' : '3');
$var = ((true) ? '2' : '3'); // '1' is true
$var = ('2');
$var = '2';

I probably should have elaborated my first comment further.

Edit: Ipang seems to have deleted his comment.

Answer 2

Strange indeed! The ternary operator appears to be left-associative in PHP, so the expression is evaluated as

$var = (true ? '1' : false) ? '2' : '3';

First the stuff in parentheses is evaluated as true, which in turn makes '2' the final value of the expression. We can fix this by using parentheses differently

$var = true ? '1' : (false ? '2' : '3');

Answer 3

Okay, I found this in the docs, with an almost identical code: 'It is recommended that you avoid "stacking" ternary expressions. PHP's behaviour when using more than one ternary operator within a single statement is non-obvious'.

Please read further here (second Note in the Ternary Operator section):
http://php.net/manual/en/language.operators.comparison.php#language.operators.comparison.ternary

Answer 4

Ipang You're welcome! Your explanation was much clearer and hence quite helpful 😊👍

Edit: Ipang has deleted his comment, but he helped me clarify my first comment.