PHP5 to PHP7 upgrade issue: array as object key parameter

Question

The problem is that when using PHP7 the expected result is different from PHP5, see following example with $object2.

I think that the three methods are equivalent from each other, but it seems not to be true.

It seems that in PHP7 the shortcut used with $object2 return the type of variable instead of the value.

Is there some environment configuration of PHP7 that makes it behave like PHP5 with respect to this issue?

$array1 = array();
$array1["Key"] = "Value"; 
$object1 = new stdClass();
$key1 = $array1["Key"];
$object1->Stream = new stdClass();
$object1->Stream->$key1 = 5;
echo json_encode($object1);

$array2 = array();
$array2["Key"] = "Value"; 
$object2 = new stdClass();
$object2->Stream = new stdClass();
$object2->Stream->$array2["Key"] = 5;
echo json_encode($object2);

$array3 = array();
$array3 = "Value"; 
$object3 = new stdClass();
$object3->Stream = new stdClass();
$object3->Stream->$array3 = 5;
echo json_encode($object3);

Result in PHP5:

{"Stream":{"Value":5}}

{"Stream":{"Value":5}}

{"Stream":{"Value":5}}

Result in PHP7:

{"Stream":{"Value":5}}

{"Stream":{"Array":{"Key":5}}}

{"Stream":{"Value":5}}

BTW: For developing, turn on notices, then you would see, that PHP emmits a notice: Notice: Array to string conversion in ... on line ... — Fabian N.
– Fabian N., Commented Oct 31, 2017 at 9:18

bumperbox · Accepted Answer · 2017-10-31 08:53:53Z

1

Try wrapping it in {}

$object2->Stream->{$array2["Key"]}

answered Oct 31, 2017 at 8:53

bumperbox

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4 Comments

PHP Developer Over a year ago

Thanks for the solution. Anyway I'm trying not to change my actual code of $object2 implementation because this is an abstract concept that I have used extensively on a big project.

Fabian N. Over a year ago

When you do not want to change code, then don't ask questions, how to modify you code, to get the desired result...

PHP Developer Over a year ago

My final question was "Is there some environment configuration of PHP7 that makes it behave like PHP5 with respect to this issue?". thanks for your support.

bumperbox Over a year ago

I don't know of any setting that will change the behaviour for php7. I am surprised php5 treats it differently to php7. Perhaps ask on the php website

B. Desai · Accepted Answer · 2017-10-31 08:53:59Z

0

You can Store array index in varaible then use this variable in object

Try follwoing code

$array1 = array();
$array1["Key"] = "Value"; 
$object1 = new stdClass();
$key1 = $array1["Key"];
$object1->Stream = new stdClass();
$object1->Stream->$key1 = 5;
echo json_encode($object1);

$array2 = array();
$array2["Key"] = "Value"; 
$tmp = $array2["Key"];
$object2 = new stdClass();
$object2->Stream = new stdClass();
$object2->Stream->$tmp = 5;
echo json_encode($object2);

$array3 = array();
$array3 = "Value"; 
$object3 = new stdClass();
$object3->Stream = new stdClass();
$object3->Stream->$array3 = 5;
echo json_encode($object3);

answered Oct 31, 2017 at 8:53

B. Desai

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1 Comment

PHP Developer Over a year ago

Your solution is the same that I have used in $object1 example. I'm searching a solution without changing the actual code of my $object2 implementation.

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