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POIsset()/Empty(), Arrays and Ternary Operator
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  1. POIsset()/Empty(), Arrays and Ternary Operator
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    copied!<p>When you need to check is there any value in array, and if not - set default value for variable, you do something like this</p> <pre><code>$authToken = isset($response['fbData']['authResponse']['accessToken']) ? $response['fbData']['authResponse']['accessToken'] : null; </code></pre> <p>I wonder, is there any way to do it somehow more readable?</p> <p>There is short version of ternary operator</p> <pre><code>$authToken = $sourceVar ?: null; </code></pre> <p>No need to repeat source here second time, but it doesn't work with arrays, because if I will use <code>$response['fbData']['authResponse']['accessToken']</code> instead of <code>$sourceVar</code> - I will get php warning message.</p> <p>I can use <code>@</code></p> <pre><code>$authToken = @$response['fbData']['authResponse']['accessToken'] ?: null; </code></pre> <p>I heard that they made "@" really fast in <code>PHP 5.4</code>, but I don't like this anyway.</p> <p>I could use something like this</p> <pre><code>$a = isset($response['fbData']['authResponse']['accessToken']) ?: null; </code></pre> <p>But in this case I will get TRUE as result, result of <code>isset()</code>.</p> <p>So, maybe somebody knows, how to do it right?</p> <p><strong>Upd1:</strong> Suggested topic <a href="https://stackoverflow.com/questions/6347694/how-can-i-create-a-new-operator-in-php">How can I create a new operator in PHP?</a> is not answers my question because there user asks "how to change PHP" and create a new operator. I do not need this. There are some answers how to do similar things without PHP modifications but they are do not work for arrays (I can't pass something like this <code>$response['fbData']['authResponse']['accessToken']</code> in function because it will generate warning message).</p> <p><strong>Upd2: Problem solved</strong>, thanks to NikiC (see comment below). The idea: Php wont generate warning message if I will pass array element as a link, so it gives us a chance to use something like this:</p> <pre><code>function myIsset (&amp;$var, $defaultVal = null) { return isset($var) ? $var : $defaultVal; } $authToken = myIsset($response['fbData']['authResponse']['accessToken']); </code></pre> <p><strong>UPD2 10/27/2015:</strong> PHP 7 has new awesome operator <code>??</code> (The null coalesce operator) that solved this problem completely and is the best way to do it: It returns its first operand if it exists and is not NULL; otherwise it returns its second operand.</p> <pre><code>$authToken = $response['fbData']['authResponse']['accessToken'] ?? 'any_default_value'; </code></pre> <p>And if requested array key does not exits - it does not generate <code>php notice</code>!</p> <p>You can use it also like this, looking for not empty value:</p> <pre><code>$username = $_GET['user'] ?? $_POST['user'] ?? 'nobody'; </code></pre>
 

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