Convert comma separated string into array

Question

I have a comma separated string, which consists of a list of tags and want to convert it to array to get a link for every tag.

Example:

$string = 'html,css,php,mysql,javascript';

I want to make it like this:

<a href="tag/html">html</a>, <a href="tag/css">css</a>, <a href="tag/php">php</a>, <a href="tag/mysql">mysql</a>, <a href="tag/javascript">javascript</a>

So the result will be a string containing comma separated links with a space after each link and with no comma after the last link.

I have this function where $arg = 'html,css,php,mysql,javascript':

function info_get_tags( $arg ) {
    global $u;

    $tagss = '';
    if ( $arg == '' ) {
        return '';
    } else {
        $tags_arr = explode( ',' , $arg );
        foreach ( $tags_arr as $tag ) {
            $tags = '<a href="' . $u . 'tag/' . $tag . '/" title="' . $tag . '">' . $tag . '</a>';
            $tagss .= $tags;
        }

        return $tagss;
    }
}

This script works for me but without commas and spaces and if we add a comma and a space here:

$tags = '<a href="' . $u . 'tag/' . $tag . '/">' . $tag . '</a>, ';

we get commas and spaces but there will be a trailing comma after the last link.

NikiC · Accepted Answer · 2011-04-30 22:59:06Z

17

Just like you exploded you can implode again:

$tags = explode(',', $arg);
foreach ($tags as &$tag) {
    $tag = '<a href="' . $u . 'tag/' . $tag . '/" title="' . $tag . '">' . $tag . '</a>';
}

return implode(', ', $tags);

edited Apr 30, 2011 at 22:59

answered Apr 30, 2011 at 22:50

NikiC

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1

this works well for me but would you tell me what's the & before $tag for?

med
– med

04/30/2011 23:06:16
Commented Apr 30, 2011 at 23:06
2

@med: The & means that you iterate by reference. That way you can modify $tag and the element in the $tags array will be modified, too.

NikiC
– NikiC

04/30/2011 23:07:46
Commented Apr 30, 2011 at 23:07
It's an operator to pass by reference, which means it's directly modifying the original value and not a copy of it.

Narf
– Narf

04/30/2011 23:09:14
Commented Apr 30, 2011 at 23:09
You should always unset the var you have just references within a foreach: foreach ( $a as &$b ) { ... unset($b); } It's somewher on PHP.net and a very good practice.

Rudie
– Rudie

04/30/2011 23:53:33
Commented Apr 30, 2011 at 23:53

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Nick · Accepted Answer · 2011-05-01 08:44:43Z

2

Here's an alternative that uses array_map instead of the foreach loop:

global $u; 
function add_html($tag){
    return('<a href="' . $u . 'tag/' . $tag . '/" title="' . $tag . '">' . $tag .  '</a>');
}
function get_tags($taglist){
    $tags_arr = array_map("add_html", explode( ',' , $taglist));
    return implode(", " , $tags_arr);
}

edited May 1, 2011 at 8:44

answered Apr 30, 2011 at 23:17

Nick

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Community · Accepted Answer · 2020-06-20 09:12:55Z

1

Try this short code

$string = 'html,css,php,mysql,javascript';

$string = explode(',', $string);
foreach( $string as $link){
echo '<a href="tag/'.$link.'">'.$link.'</a>';
}

edited Jun 20, 2020 at 9:12

CommunityBot

11 silver badge

answered Aug 19, 2015 at 20:01

Cross

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prodigitalson · Accepted Answer · 2011-04-30 22:48:59Z

0

Easiest way is to the html into an array (each tag link is an array element) and then implode on ,...

if ( $arg == '' ) {

    return '';

} else {

    $tags_arr = explode( ',' , $arg );
    $tags  = array();
    $tagtpl = '<a href="%s" title="%s">%s</a>';

    foreach ( $tags_arr as $tag ) {
        $url = $u . 'tag/' . $tag . '/';
        $tags[] = sprintf($tagtpl, $url, $tag, $tag);

    }

    return implode(', ', $tags);

}

answered Apr 30, 2011 at 22:48

prodigitalson

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Igor · Accepted Answer · 2011-04-30 22:50:28Z

0

Try this

$tagss = trim($tagss);    
return substr($tagss, 0 , strlen($tagss)-1);

answered Apr 30, 2011 at 22:50

Igor

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You can just write substr($tagss, 0, -2) ;)

NikiC
– NikiC

04/30/2011 22:56:59
Commented Apr 30, 2011 at 22:56
@nikic yeap you're right, faster and nicer, but rtrim is even better

Igor
– Igor

04/30/2011 23:01:23
Commented Apr 30, 2011 at 23:01

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Arjan · Accepted Answer · 2011-04-30 22:53:54Z

0

Why not put all tags in an array when you are creating them, and later explode the array and add the commas and spaces between the tags.

foreach ( $tags_arr as $tag ) {
    $tags = '<a href="' . $u . 'tag/' . $tag . '/" title="' . $tag . '">' . $tag . '</a>';
    $tagss[] = $tags;
}
$tagss = explode(', ', $tagss);

answered Apr 30, 2011 at 22:53

Arjan

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mario · Accepted Answer · 2011-04-30 22:54:13Z

0

The workaround(!) would be to remove the unwanted trailing characters afterwards:

$tagss = rtrim($tagss, ", ");

This rtrim removes any mix of spaces and commas from the right end of the string.

Btw, you could use str_getcsv instead of explode, which also handles input spaces better.

answered Apr 30, 2011 at 22:54

mario

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Narf · Accepted Answer · 2011-04-30 23:06:54Z

0

function info_get_tags($arg)
{
    global $u;
    if (empty($arg)) return '';
    return ltrim(preg_replace('/([^\,]+)/', ' <a href="' . $u . '/${1}/" title="${1}">${1}</a>', $arg));
}

answered Apr 30, 2011 at 23:06

Narf

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Alphons · Accepted Answer · 2016-03-24 22:02:54Z

0

$string = 'html,css,php,mysql,javascript';

puts $string.split(/,/).map { |tag| "<a href=\"tag/#{tag}\">#{tag}</a>"}.join(", ")

result:

<a href="tag/html">html</a>, <a href="tag/css">css</a>, <a href="tag/php">php</a>, <a href="tag/mysql">mysql</a>, <a href="tag/javascript">javascript</a>

answered Mar 24, 2016 at 22:02

Alphons

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Rudie · Accepted Answer · 2014-09-19 21:27:25Z

-3

Another solution:

$html = trim(preg_replace('/([^,]+)/', ' <a href="/tags/\1" title="\1">\1</a>', $string));

Or if you have to html encode the tags (always smart, since you're creating html from text):

$html = trim(preg_replace_callback('/([^,]+)/', function($match) {
    $tag = $match[1];
    return ' <a href="/tags/' . urlencode($tag) . '" title="' . htmlspecialchars($tag) . '">' . htmlspecialchars($tag) . '</a>';
}, $string));

So this $string would work too: "tag with space,html,css,php,mysql,javascript"

More regex is always good!

edited Sep 19, 2014 at 21:27

answered May 1, 2011 at 0:00

Rudie

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