Php首先拆分然后循环

I have a string like this:

$d = 'game, story, animation, video';

And I want to change it to a result like this:

<a href="game">game</a>, <a href="story">story</a>, <a href="animation">animation</a>, <a href="video">video</a>

So I think I have to split $d by ',' then use a for loop.

I have tried this:

$d = 'game, story, animation, video';

list($a, $b, $c, $d) = explode(" ,", $d);

But how do I split it if I don't know how many ',' are going to be there, and reach the desired result?

There are many ways this could be accomplished here is one. by using a foreach loop you should be able to accomplish what you are attempting to do.

You also need to assign you array items correctly, by casting as a string and using the [ ] shorthand or using array()

$d = "game, story, animation, video";
$out = '' ;

foreach(explode(",",$d) as $item){
    $out .= "<a href='$item' />$item</a>";
}

echo $out;

and if you need the , between you could use this

$d = "game, story, animation, video";
$out = [] ;

foreach(explode(",",$d) as $item){
    $out []= "<a href='$item' />$item</a>";
}

echo implode(",",$out); 

read more here

implode

explode

foreach

The key here is to realise that you can break this line into two parts:

list($a, $b, $c, $d) = explode(" ,", $d);

First, it takes the string $d and splits it into an array, let's call it $items:

$items = explode(" ,", $d);

Then the list() construct takes the items from that array and puts them into separate named variables:

list($a, $b, $c, $d) = $items;

If you don't know how many items are going to be in the list, you can just skip the second step, and work with the array, probably using a foreach loop:

foreach ( $items as $item ) {
    echo "Doing something with '$item'...";
}

<?php

$in  = 'game, story, animation, video';
$out = preg_replace('@([a-z]+)@', '<a href="$1">$1</a>', $in);
var_dump($out);

Or:

$tags = explode(',', $in);
$tags = array_map('trim', $tags);
$out  = [];
foreach($tags as $tag)
    $out[] = '<a href="' . $tag . '">' . $tag . '</a>';

$out = implode(', ', $out);
var_dump($out);

Output for each:

string(112) "<a href="game">game</a>, <a href="story">story</a>, <a href="animation">animation</a>, <a href="video">video</a>"