PHP Loop error - only part of the loop is looped?

Question

Me and several friends taking the same programming course have been confused by this for hours so far, hopefully someone here can help. The aim is to take a list of urls, split by new lines, prepend [ img] and append [/ img] for each URL, as suitable for a bulletin board. The actual code includes a switch to allow for both [ img] and [ thumb] bbcodes, but both have the same effect. Instead of outputting

[ img]1[/ img]
[ img]2[/ img]

it outputs

[ img]1
2[ /img]

The same happens for any number of URLs. Here's the code I am using.

   <?php

    $url_f = (isset($_POST['text'])) ? $_POST['text'] : false;
    $thumb = (isset($_POST['type'])) ? $_POST['type'] : false;
    $urls = ($url_f) ? explode('\n',$url_f) : '';

    ?>

    <textarea rows='20' cols='40' readonly='1'>


    <?php
    switch ($thumb){
        case 'img':
            for ($i = count($urls)-1; $i >= 0; $i--)
            {
                echo "[img]". $urls[$i] ."[/img]\n";
            }
            break;

        default:
            break;

        case 'thumb':
            for ($i = count($urls)-1; $i >= 0; $i--)
            {
                echo '[thumb]'. $urls[$i] ."[/thumb]\n";
            }
            break;

    }

    ?>

    </textarea>

default should come last you know, otherwise it will skip anything beyond it. — Madara's Ghost
– Madara's Ghost, Commented Oct 25, 2011 at 20:04
That switch is really funky. Also have personally never seen the default on anything but the last line of the switch {}. Is $urls actually being populated as expected? — Tim
– Tim, Commented Oct 25, 2011 at 20:07
Yes, I've tried echoing out $urls[0], $urls[1], etc, they all work fine. — SatansFate
– SatansFate, Commented Oct 25, 2011 at 20:09

Timiz0r · Accepted Answer · 2011-10-25 20:15:29Z

1

There are three different types of newlines: \r, \n, and \r\n. I don't do much web development, but different OSes will still probably send different newlines, so you'll have to do some checking to find out what character(s) to split with.

~~In your code, since \n isn't working, the newline is probably \r\n or \r.~~

Edit: The single quoted string literal may be the problem.

edited Oct 25, 2011 at 20:15

answered Oct 25, 2011 at 20:08

Timiz0r

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4 Comments

SatansFate Over a year ago

That makes sense. How would I go about checking? Could I just explode it, then check the length?

Timiz0r Over a year ago

I missed something since I haven't touched PHP in a while. The single quotes you used should be replaced with double quotes in order for the escape sequences to work. Try that, and, if there's still a problem, I'll post code.

SatansFate Over a year ago

Aaaaah! Jeez, reminds me why I hate PHP so much. Spending hours pondering over the difference between single and double quotes...That fixed it. Thanks a lot to everyone who helped.

Marc B Over a year ago

@user1013452: it's not just a PHP-ism. Many (most? all?) scripting languages that use $ for variables differentiate between ' and " strings.

rodneyrehm · Accepted Answer · 2011-10-25 20:17:51Z

1

Your Problem is '\n' !== "\n". The former is treated as "backslash n", while the latter is processed to the line feed character (ASCII 0xA, bein LF). See Double Quoted Strings for more info.

Regarding your loop, you might want to look into foreach.

answered Oct 25, 2011 at 20:17

rodneyrehm

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