有php foreach和通过引用传递的困难

Question

I'm pulling some data from a database (with a function I have called query), and I want to add another key/value pair to each result, ie:

$items = query("SELECT * FROM items");

foreach($items as &$item) {
    $item['fixedname'] = str_replace(' ','_',$item['name']);
}

Now I want to put these on an html view, ie:

<?php foreach($items as $item): ?>
<div id="<?= $item['fixedname'] ?>" ><?= $item['name'] ?></div>
<?php endforeach; ?>

However, this doesn't output correctly. For instance, when the query returns two items, the loop in the php outputs the same thing twice. If there are three: it outputs the first one, then two of the second one. What's the problem here?

Answer 1

When modifying using foreach() I've had weird results on occasion. I use

foreach ($items as $key=>$value) {
    $items[$key] = modified($value);
}

Or, why not do it in the SQL SELECT your, fields, here, REPLACE(name, ' ', '-') AS fixedname

Answer 2

You could do a normal for loop

<?php 
    for($i=0; $i < count($items); $i++){
        $items[$i]['fixedname'] = str_replace(' ','_',$items[$i]['name']);
    }
?>

Then everything will be ready when you go to your next foreach.

Answer 3

The data returned on the right side of the foreach is a copy of the data, it can't be modified directly. Instead you need to fetch both the $key (the ID of the item in the array) and the $item. By letting PHP telling you the $key you don't need to worry about whether the array is normal (eg having indexes of 0,1,2,...) and associative.

This example would walk the $items array and add 'fixedname' into it.

foreach($items as $key => $item) {
    $items[$key]['fixedname'] = str_replace(' ','_',$item['name']);
}

Answer 4

u have bunch of wrong things

1 - dont use mysql , use PDO or mysqli instead

2 - $items = query("SELECT * .... --->Call to undefined function query()

change it to

$items = mysql_query("SELECT *  ....

3 - Invalid argument supplied for foreach() ,

you missed to fetch your query

try this whole code

 $items = mysql_query("SELECT * FROM items");

 ?>
<?php while ($row = mysql_fetch_array($items) ) {?>
 <div id="<?php echo $row['fixedname'] ;?>" ><?php echo $row['name']; ?></div>
<?php } ?>