How Can I Correctly Implement Nested Ternary Operators in PHP to Avoid Unexpected Results?

Nested Ternary Operators in PHP: A Puzzle Solved

Nested ternary operators provide a concise and powerful way to conditionally assign values in PHP. However, when multiple operators are used, proper syntax becomes crucial.

The Problem

Consider the following code:

$province = 7;
$Myprovince = (
($province == 6) ? "city-1" :
($province == 7) ? "city-2" :
($province == 8) ? "city-3" :
($province == 30) ? "city-4" : "out of borders"
);

Despite intending to select a city based on the province value, the code assigns "city-4" to $Myprovince for every field.

The Solution

The issue lies in the lack of parentheses. Each ternary operator must be properly nested to ensure correct evaluation. The updated code below fixes the problem:

$province = 7;
$Myprovince = (
($province == 6) ? "city-1" :
  (($province == 7) ? "city-2" :
   (($province == 8) ? "city-3" :
    (($province == 30) ? "city-4" : "out of borders")))
);

How it Works

The innermost ternary operator evaluates the condition ($province == 8) and assigns "city-3" if true or continues to the next operator if false.

The middle ternary operator checks if $province is equal to 7 and assigns "city-2" if true or proceeds to the next operator.

Finally, the outermost ternary operator evaluates the condition ($province == 6) and assigns "city-1" if true or proceeds to the remaining options, eventually assigning "city-4" if $province is 30 or "out of borders" otherwise.

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