Why would this echo "NULL"? In my would it would be decoded to an empty array.
Is it something obvious I'm missing?
<?php
$json = json_encode(array());
$json_decoded = json_decode($json, true);
// same with json_decode($json);
if ($json_decoded == null){
echo "NULL";
} else
{
echo "NOT NULL";
}
?>
This is because array()==NULL. It does not check the object type in this case.
gettype(null) returns null, whereas
gettype(array()) returns array. Hope you got the difference.
Probably what you need is
if ($json_decoded === null) {
echo "NULL";
} else
{
echo "NOT NULL";
}
print_r the $json_decoded value it gives the empty array back. :)
$json = json_encode(array());
$json_decoded = json_decode($json, true);
if ($json_decoded == null){
print_r($json_decoded);
} else
{
echo "NOT NULL";
}
outputs : Array ( ) This is because with == operator the empty array gets type juggled to null
This must do the trick
if ($json_decoded === null)
Example from the manual:
<?php
$a = array('<foo>',"'bar'",'"baz"','&blong&', "\xc3\xa9");
echo "Normal: ", json_encode($a), "\n";
echo "Tags: ", json_encode($a, JSON_HEX_TAG), "\n";
echo "Apos: ", json_encode($a, JSON_HEX_APOS), "\n";
echo "Quot: ", json_encode($a, JSON_HEX_QUOT), "\n";
echo "Amp: ", json_encode($a, JSON_HEX_AMP), "\n";
echo "Unicode: ", json_encode($a, JSON_UNESCAPED_UNICODE), "\n";
echo "All: ", json_encode($a, JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_QUOT | JSON_HEX_AMP | JSON_UNESCAPED_UNICODE), "\n\n";
$b = array();
echo "Empty array output as array: ", json_encode($b), "\n";
echo "Empty array output as object: ", json_encode($b, JSON_FORCE_OBJECT), "\n\n";
$c = array(array(1,2,3));
echo "Non-associative array output as array: ", json_encode($c), "\n";
echo "Non-associative array output as object: ", json_encode($c, JSON_FORCE_OBJECT), "\n\n";
$d = array('foo' => 'bar', 'baz' => 'long');
echo "Associative array always output as object: ", json_encode($d), "\n";
echo "Associative array always output as object: ", json_encode($d, JSON_FORCE_OBJECT), "\n\n";
?>
Output:
Normal: ["<foo>","'bar'","\"baz\"","&blong&","\u00e9"]
Tags: ["\u003Cfoo\u003E","'bar'","\"baz\"","&blong&","\u00e9"]
Apos: ["<foo>","\u0027bar\u0027","\"baz\"","&blong&","\u00e9"]
Quot: ["<foo>","'bar'","\u0022baz\u0022","&blong&","\u00e9"]
Amp: ["<foo>","'bar'","\"baz\"","\u0026blong\u0026","\u00e9"]
Unicode: ["<foo>","'bar'","\"baz\"","&blong&","é"]
All: ["\u003Cfoo\u003E","\u0027bar\u0027","\u0022baz\u0022","\u0026blong\u0026","é"]
Empty array output as array: []
Empty array output as object: {}
Non-associative array output as array: [[1,2,3]]
Non-associative array output as object: {"0":{"0":1,"1":2,"2":3}}
Associative array always output as object: {"foo":"bar","baz":"long"}
Associative array always output as object: {"foo":"bar","baz":"long"}
You need to use strict equality operator ===, observe for yourself:
$json = json_encode(array());
var_dump($json); // string(2) "[]"
$json_decoded = json_decode($json, true);
var_dump($json_decoded); // array(0) { }
So doing:
$json = json_encode(array());
$json_decoded = json_decode($json, true);
if ($json_decoded === null)
{
echo "NULL";
} else
{
echo "NOT NULL";
}
would rightly go in else condition printing NOT NULL
If your data includes some \n json_decode might fail silently too.
$json_decoded === null?newkeyword for an array in PHP.