Edit report at https://bugs.php.net/bug.php?id=70937&edit=1
ID: 70937
User updated by: David dot Gausmann at measX dot com
Reported by: David dot Gausmann at measX dot com
Summary: natsort/natcasesort change key data type
Status: Not a bug
Type: Bug
Package: Arrays related
PHP Version: 5.6.15
Block user comment: N
Private report: N
New Comment:
Hello again,
I've read the documentation before creating this bug report, but I still didn't get it
after I found out how it behaves. The documentation simply doesn't sound like "be aware
your numeric keys will turn into strings".
It says:
>> This function implements a sort algorithm that orders alphanumeric strings in the way a
>> human being would while maintaining key/value associations. This is described as a "natural
>> ordering". An example of the difference between this algorithm and the regular computer string
>> sorting algorithms (used in sort()) can be seen in the example below. <<
The information must be hidden in "while maintaining key/value associations", but it is
not clear which consequences this has.
An additional information like this would be fine:
>> The maintenance of the key/value associations is performed via conversion of the numeric
>> keys into strings. Unlike sort() elements will be accessed after sorting via their old index (e. g.
>> $array[0] will return the element with index 0 and not the first element). If you don't need
>> this behaviour, call array_values after sort or use usort with 'strnatcasecmp'. <<
The same goes for natcasesort. It would be very fine when you add something like that to the
documentation.
Kind Regards
David Gausmann
Previous Comments:
------------------------------------------------------------------------
[2015-11-19 02:57:51] laruence@php.net
Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to
report
a bug at http://bugs.php.net/how-to-report.php
------------------------------------------------------------------------
[2015-11-18 18:23:29] nhojohl at gmail dot com
This is because natsort and natcasesort maintain the key association (it does not re-key the array).
An array must have sequential keys in order for json_encode to encode it as a natural array,
otherwise it converts the array to an associative array (an object) and maintains the key value
association.
If you use array_values on the resulting array after sorting it; it'l resolve your issue
(relevant reference: http://php.net/manual/en/function.natcasesort.php#32610)
Example:
$array = array('b', 'a', 'c');
natsort($array);
$array = array_values($array);
echo "After natsort:<br>\r\n", json_encode($array), "<br>\r\n";
$array = array('b', 'a', 'c');
natcasesort($array);
$array = array_values($array);
echo "After natcasesort:<br>\r\n", json_encode($array), "<br>\r\n";
------------------------------------------------------------------------
[2015-11-18 13:57:16] David dot Gausmann at measX dot com
Description:
------------
I am using php to transfer arrays via JSON.
After using natsort/natcasesort for sorting the resulting data aren't JSON arrays anymore. This
happens because natsort/natcasesort are changing the datatype of the array keys from int to string
(but only when the data becomes sorted; otherwise the key data type won't change).
A workaround is it to use usort with strnatcmp/strnatcasecmp as second parameter.
Test script:
---------------
<?php
$array = array('b', 'a', 'c');
echo "After creation:<br>\r\n", json_encode($array), "<br>\r\n";
$array = array('b', 'a', 'c');
sort($array);
echo "After sort:<br>\r\n", json_encode($array), "<br>\r\n";
$array = array('b', 'a', 'c');
rsort($array);
echo "After rsort:<br>\r\n", json_encode($array), "<br>\r\n";
$array = array('b', 'a', 'c');
natsort($array);
echo "After natsort:<br>\r\n", json_encode($array), "<br>\r\n";
$array = array('b', 'a', 'c');
natcasesort($array);
echo "After natcasesort:<br>\r\n", json_encode($array), "<br>\r\n";
$array = array('b', 'a', 'c');
usort($array, 'strnatcmp');
echo "After usort(strnatcmp):<br>\r\n", json_encode($array),
"<br>\r\n";
?>
Expected result:
----------------
In all used sort functions the result should be an array like
["a","b","c"].
Actual result:
--------------
Instead natsort/natcasesort return
{"1":"a","0":"b","2":"c"} in JSON
syntax.
Only the other sort functions return an array like ["a","b","c"].
------------------------------------------------------------------------
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Edit this bug report at https://bugs.php.net/bug.php?id=70937&edit=1