Imploding variables into comma seperated string

@phantomlimbOct 17.2009

I have a PHP post form that posts up to 4 variables. I need whatever variables are passed to be combined into one comma seperated string (eg variable1,variable2,variable3,variable4). This i can do with the code below.

[CODE]$combo = array($one, $two, $three, $four); $list = implode(“,”, $combo);[/CODE]

my problem is that the form fields are optional by design so that the user doesn’t always post all 4 variables. Sometimes they will post 1, sometimes they will post all 4. So if a user only selects two fields and submits the form i will end up with a string looking like:
~~[COLOR=”Red”]~~variable1,variable2,,[/COLOR]
when what i really want is (note the removal of the trailing commas at the end of the string):
~~[COLOR=”DarkGreen”]~~variable1,variable2[/COLOR]

Anyone got an idea on how i could strip any trailing commas from the end of the string?

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PHP

4 Comments(s) _↴

@MindzaiOct 17.2009 — #Here's two options, first one is my preference and that is store the optional form elements as an array and just implode that:

[code=html]<input type="checkbox" name="foo[]" value="1" />
 <input type="checkbox" name="foo[]" value="1" />
 <input type="checkbox" name="foo[]" value="1" />
 <input type="checkbox" name="foo[]" value="1" />[/code]

[code=php]implode(',', $_POST['foo']);[/code]

Otherwise if all the commas will be at the end you can use rtrim:

[code=php]$string = rtrim($string, ',');[/code]

@phantomlimbauthorOct 17.2009 — #Thanks for the reply, you're first option is interesting, i didn't think of that.

i gave it a try, but i must be doing something wrong as i get the Warning: implode() [function.implode]: Invalid arguments passed.

i set the form up as you suggested:

[CODE]<input type="checkbox" name="foo[]" value="1" />
 <input type="checkbox" name="foo[]" value="2" />
 <input type="checkbox" name="foo[]" value="3" />
 <input type="checkbox" name="foo[]" value="4" />[/CODE]

and added the new implode to the list variable.

[CODE]$list = implode(',', $_POST['foo']); [/CODE]

this is going to sound stupid, but you mentioned storing the form elements as an array, how do i go about that? Is there something i have to add to the brackets in foo[]?

@MindzaiOct 17.2009 — #I assume you are sending this form via POST and not GET? If not you will need to use the $_GET superglobal instead. The following code is a complete example:

[code=php]
 <?php
 if (isset($_POST['foo'])) {
 echo implode(',', $_POST['foo']);
 }
 ?>
 
 <form action="<?php echo $_SERVER['PHP_SELF'] ?>" method="post">
 <input type="checkbox" name="foo[]" value="1" />
 <input type="checkbox" name="foo[]" value="1" />
 <input type="checkbox" name="foo[]" value="1" />
 <input type="checkbox" name="foo[]" value="1" />
 <button type="submit">Go</button>
 </form>
 [/code]

this is going to sound stupid, but you mentioned storing the form elements as an array, how do i go about that? Is there something i have to add to the brackets in foo[]?[/quote]

There's no such thing as a stupid question if you don't know the answer! The array is achieved by including square brackets in the name attributes of the elements. In the above example, you are essentially creating a [B]foo[/B] array with 4 elements which will have numerical keys (empty square brackets will be automatically sequentially keyed for you). You can also specify the index to create an associative array (or a numerically indexed array with custom indeces):

[code=html]
 <input type="checkbox" name="foo[beer]" value="1" />
 <input type="checkbox" name="foo[whiskey]" value="2" />
 <input type="checkbox" name="foo[vodka]" value="3" />
 <input type="checkbox" name="foo[lemonade]" value="4" />
 [/code]

You will then have the following in $_POST (depending of which elements were provided of course):

<i>
 </i>Array
 (
 [foo] =&gt; Array
 (
 [beer] =&gt; 1
 [whiskey] =&gt; 1
 [vodka] =&gt; 1
 [lemonade] =&gt; 1
 )
 
 )

You can even go to multiple dimensions:

[code=html]
 <input type="checkbox" name="foo[beer][budweiser]" value="1" />
 <input type="checkbox" name="foo[beer][fosters]" value="1" />
 <input type="checkbox" name="foo[beer][heineken]" value="1" />
 <input type="checkbox" name="foo[whiskey]" value="1" />
 <input type="checkbox" name="foo[vodka]" value="1" />
 <input type="checkbox" name="foo[lemonade]" value="1" />
 [/code]

<i>
 </i>Array
 (
 [foo] =&gt; Array
 (
 [beer] =&gt; Array
 (
 [budweiser] =&gt; 1
 [fosters] =&gt; 1
 [heineken] =&gt; 1
 )
 
 <i>    </i>        [whiskey] =&gt; 1
 <i>    </i>        [vodka] =&gt; 1
 <i>    </i>        [lemonade] =&gt; 1
 <i>    </i>    )
 
 )

@phantomlimbauthorOct 17.2009 — #Cheers! Thanks for the in-depth response, that works great Mindzai. Much appreciated.

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