在三元运算符中使用 return

Question

I'm trying to use return in a ternary operator, but receive an error:

Parse error: syntax error, unexpected T_RETURN 

Here's the code:

$e = $this->return_errors();
(!$e) ? '' : return array('false', $e);

Is this possible?

Thanks!

Answer 1

This is the correct syntax:

return  !$e ? '' : array('false', $e);

Answer 2

Close. You'd want return condition?a:b

Answer 3

It doesn't work in most languages because return is a statement (like if , while , etc.), rather than an operator that can be nested in an expression. Following the same logic you wouldn't try to nest an if statement within an expression:

// invalid because 'if' is a statement, cannot be nested, and yields no result
func(if ($a) $b; else $c;); 

// valid because ?: is an operator that yields a result
func($a ? $b : $c); 

It wouldn't work for break and continue as well.

Answer 4

No it's not possible, and it's also pretty confusing as compared to:

if($e) {
    return array('false', $e);
}

Answer 5

No. But you can have a ternary expression for the return statement.

return (!$e) ? '' : array('false', $e);

Note: This may not be the desired logic. I'm providing it as an example.

Answer 6

Plop,

if you want modify your return with ternary?

it's totally possible.

In this exemple, i have a function with array in parameters. This exemple function is used to parse users array. On return i have an array with user id and user username. But what happens if I do not have any users?

<?php

public funtion parseUserTable(array $users) {
   $results = [];
   foreach ($users as $user) {
      $results[$users['id']] = $user['username'];
   }
  return $results ?: array('false', $e, "No users on table."); // Ternary operator.
}

Sorry for my bad english, i'm french user haha.

ND.

Answer 7

No, that's not possible. The following, however, is possible:

$e = $this->return_errors();
return ( !$e ) ? '' : array( false, $e );

Hope that helps.