Edit report at https://bugs.php.net/bug.php?id=55772&edit=1
ID: 55772
User updated by: rick dot foos at solengtech dot com
Reported by: rick dot foos at solengtech dot com
Summary: is_array throws E_NOTICE on undefined array
elements, isset does not.
Status: Open
Type: Bug
Package: Scripting Engine problem
Operating System: Fedora/Ubuntu
PHP Version: 5.3.8
Block user comment: N
Private report: N
New Comment:
Sorry for blithering, long day, and most of the comments on arrays involved
lectures. isset works, is_array returns true/false correctly, but throws an
E_NOTICE.
is_array is a test, and should not throw an error when the test is false.
Previous Comments:
------------------------------------------------------------------------
[2011-09-24 15:14:42] anonymous at nowhere dot never
>is_array is the correct call to use.
What are you blithering about? I think you mean isset(). is_array has nothing
to do with it.
Anyway, the problem you're having is because you're treating $data_array as a
multidimensional array. It's not. PHP has arrays of arrays, not
multidimensional arrays (in languages like this you could make a triangular
array if you wanted). So if the row is not defined then testing isset on the
row's column will complain about the undefined row. So you have to isset on the
row to make sure that's there first before you can test its column elements.
E.g.:
if (isset($data_array[$r + 1]) && isset($data_array[$r + 1][$c + 1])) ...
Or like this:
for ($r = 0; $r < $row_count; $r++) {
echo "<tr>";
if (isset($data_array[$r + 1])) {
$row = $data_array[$r + 1];
for ($c = 0; $c < $col_count; $c++) {
if (isset($row[$c + 1])) {
$data = $row[$c + 1];
} else {
$data = null;
}
echo "<td>", $data;
}
} else {
echo str_repeat("<td>", $col_count);
}
}
------------------------------------------------------------------------
[2011-09-24 00:29:27] rick dot foos at solengtech dot com
Description:
------------
I have a sparse matrix, that needs each element to display on an html page. So
when the matrix is loaded with defined values there are many undefined values,
6158 for example.
This is displayed as a square matrix using an HTML table - A conflict between
good PHP programming and HTML programming. The undefined elements need some
html, so the 'for loops' must touch each element of the array to display the
square set of values.
is_array is the correct call to use. It tests array elements, and returns true
or false if they are valid or not.
While the is_array function returns true and false - PHP still issues the
warning message. is_array is a test, not an operation on a null value, and
therefore not bad programming requiring a message.
http://rickfoosusa.blogspot.com/2011/09/howto-clear-php-undefined-offset.html
Test script:
---------------
$data_array=array();
$data_array[2][10] = "defined";
$row_count = 10;
$col_count = 10;
//...fill with the defined values...many values undefined.
for ($r = 0; $r < $row_count; $r++)
{
echo "<tr>";
for ($c = 0; $c < $col_count; $c++)
{
if (isset($data_array[$r+1][$c+1])){
$data = $data_array[$r+1][$c+1];
} else {
$data = NULL;
}
echo "<td>";
}
}
Expected result:
----------------
True or False depending if the array element is valid.
Actual result:
--------------
True or False depending if the array element is valid.
PHP Notice: Undefined offset: 118 in /usr/share/resultsdb/www/index.php on
line 465, referer: http://134.86.96.216/resultsdb/index.php?
------------------------------------------------------------------------
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Edit this bug report at https://bugs.php.net/bug.php?id=55772&edit=1
