possible limitation of implode function in PHP

问题:

I have the following code that is not returning as I expected. I was hoping the final result would be a string:

$organizers = array_unique($organizers);     // this returns correctly
$organizers = implode(', ', $organizers);    // this returns nothing
var_dump($organizers);                        // no data appears here
exit;

The array_unique() function is returning data correctly and I can see the array it returns. To start, the $organizers array is a simple 1-D array of strings that all have small lengths under 20 chars. I think the issue might be that $organizers is more than 10,000 indices long. Are there limitations on the length of an array that can be imploded? Are there work-arounds for that? I cannot find anything in the manual, but I have tested this code thoroughly and I believe the error must be on implode().

回答1:

I dont' know if there is a limitation, but what comes to my mind is taht you are also transforming an array into a string. This shouldn't be the problem in PHP, but try calling it a different variable for the result of implode?

$organizers        = array_unique($organizers);     // this returns correctly
$organizers_string = implode(', ', $organizers);    // this returns nothing

// This gives it a different space 

回答2:

Edit: And if for some reason implode() is still problematic.

$organizers = array_unique($organizers);
$neworganizers = "";
for($i = 0; $i < sizeof($organizers); $i++)
{
    $neworganizers .= $organizers[$i];
    if($i != sizeof($organizers) - 1)
    {
        $neworganizers .= ", ";
    }
}

//$neworganizers is now the equivalent of what .implode() should return when called on $organizers

$organizers = array();
$organizers[0] = "value1";
$organizers[1] = "value2";
$organizers[2] = "value3";
$organizers[3] = "value3";
$organizers = array_unique($organizers);     // strips out last index
$organizers = implode(', ', $organizers);    // returns string of "value1, value2, value3"
echo $organizers;

This seemed to work on writecodeline.com/php/

I've also experienced issues with older php builds when I've tried to explode/implode by a string with special characters in it and they were encapsulated by single quotes. I know it sounds crazy, but the double quotes might be necessary on some servers.

Reference: personal experience doing work on older production servers.

回答3:

I'd hate to think I'm stating the obvious, but doesn't implode only take a string as an argument? Maybe it should be something more like this...

$organizers = array_unique($organizers);

//I'm guessing what you wanted was an array of arrays?
$neworganizers = array();
for($i = 0; $i < sizeof($organizers); $i++)
{
    $neworganizers[$i] = implode(", ", $organizers);
}
print_r($neworganizers);