Using nested ternary operators [duplicate]

Question

I've been trying to use isset() in nested form like below:

isset($_POST['selectedTemplate'])?$_POST['selectedTemplate']:isset($_GET['selectedTemplate'])?$_GET['selectedTemplate']:0

But seems I'm missing something. Can anyone assist me how to do it?

Nesting the ternary operator really isn't recommended because it is completely non-intuitive: if you need to nest, you really should use full if/else syntax because it's much easier to read both for yourself and others — Mark Baker
– Mark Baker, Commented Jan 4, 2012 at 22:58
This bears the question why your form can be submitted via POST and GET in the first place. HTTP verbs have certain semantics to them.. — Gordon
– Gordon, Commented Jan 4, 2012 at 23:13

Joseph Silber · Accepted Answer · 2017-01-31 14:43:56Z

71

Wrap it in parentheses:

$selectedTemplate = isset($_POST['selectedTemplate'])
                  ? $_POST['selectedTemplate']
                  : (
                       isset($_GET['selectedTemplate'])
                       ? $_GET['selectedTemplate']
                       : 0
                  );

Or even better, use a proper if/else statement (for maintainability):

$selectTemplate = 0;

if (isset($_POST['selectedTemplate'])) {
    $selectTemplate = $_POST['selectedTemplate'];
} elseif (isset($_GET['selectedTemplate'])) {
    $selectTemplate = $_GET['selectedTemplate'];
}

However, as others have pointed out: it would simply be easier for you to use $_REQUEST:

$selectedTemplate = isset($_REQUEST['selectedTemplate'])
                  ? $_REQUEST['selectedTemplate']
                  : 0;

edited Jan 31, 2017 at 14:43

answered Jan 4, 2012 at 22:56

Joseph Silber

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6 Comments

hakre Over a year ago

Just a note: $_REQUEST takes more than $_POST and $_GET and the order can vary.

Barry Chapman Over a year ago

Cheers. Exactly what I needed, I did not know you had to wrap the whole second part of the statement in parenthesis.

johnny Over a year ago

Good on the maintainability.

Camille Goudeseune Over a year ago

C/C++ don't need parens for nested ?:, stackoverflow.com/q/18237432/2097284, so someone who comes to PHP from there gets a surprise.

Joseph Silber Over a year ago

@CamilleGoudeseune - C/C++ uses right-associativity by default for ternary expressions, while PHP uses left-associativity by default. In reality, left-associativity is almost never what you want, so PHP's default doesn't really make much sense. In fact, this is being deprecated in PHP 7.4.

|

Risul Islam · Accepted Answer · 2020-12-29 12:10:01Z

10

As of PHP 7 we can use Null coalescing operator

$selectedTemplate = $_POST['selectedTemplate'] ?? $_GET['selectedTemplate'] ?? 0;

edited Dec 29, 2020 at 12:10

Risul Islam

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answered Apr 5, 2016 at 7:41

Adersh

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Comments

Sergey Chizhik · Accepted Answer · 2016-02-29 15:51:37Z

A little investigate here, and I guess, I've found real answer :)

Example code:

<?php

$test = array();
$test['a'] = "value";


var_dump(
    isset($test['a'])
        ? $test['a']
        : isset($test['b'])
            ? $test['b']
            : "default"
);

Be attentive to round brackets, that I've put.

I guess, you're waiting to get similar behavior:

var_dump(
    isset($test['a'])
        ? $test['a']
        : (isset($test['b'])  // <--  here
            ? $test['b']
            : "default")      // <--  and here
);

But! Real behavior looks like this:

var_dump(
    (isset($test['a'])        // <--  here
        ? $test['a']
        : isset($test['b']))  // <--  and here
            ? $test['b']
            : "default"
);

General mistake was, that you've missed notice: Undefined index.

Online shell.

spex · Accepted Answer · 2017-02-03 18:54:52Z

4

It's simpler to read if we write ternary in the following manner:

$myvar = ($x == $y)
  ?(($x == $z)?'both':'foo')
  :(($x == $z)?'bar':'none');

But ternary operators are short, effective ways to write simple if statements. They are not built for nesting. :)

edited Feb 3, 2017 at 18:54

spex

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answered Dec 19, 2012 at 5:22

Govind Totla

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Comments

Community · Accepted Answer · 2023-11-17 20:38:18Z

3

You might have an easier time simply using the $_REQUEST variables:

"$_REQUEST is an associative array that by default contains the contents of $_GET, $_POST and $_COOKIE."

https://www.php.net/manual/en/reserved.variables.request.php

edited Nov 17, 2023 at 20:38

CommunityBot

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answered Jan 4, 2012 at 22:58

Fletch

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Comments

Carlos · Accepted Answer · 2017-06-01 12:17:19Z

2

I believe this will work:

$test = array();
$test['a'] = 123;
$test['b'] = NULL;


$var = (isset($test['a']) ? $test['a'] : (!isnull($test['b']) ? $test['b'] : "default"));

echo $var;

answered Jun 1, 2017 at 12:17

Carlos

211 bronze badge

Comments

mario · Accepted Answer · 2012-01-04 22:58:41Z

1

Instead of the ternary with the ambiguous precedence, you could just use $_REQUEST instead of the fiddly $_GET and $_POST probing:

 isset($_REQUEST['selectedTemplate']) ? $_REQUEST['selectedTemplate'] : 0

This is precisely what it is for.

answered Jan 4, 2012 at 22:58

mario

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