Delete Trailing Commas In PHP

14th April 2009 - 3 minutes read time

Converting an array of information into a string is easy, but when you are doing this for insertion into a database having trailing commas is going to mess up your SQL statements.

Take the following example, which takes an array of values and converts them into a string of values. This practice is quite common in PHP database manipulation.

$values = array('one', 'two', 'three', 'four', 'five');
$string = '';
 
foreach ( $values as $val ) {
    $string .= '"'.$val.'", ';
}
 
echo $string; // prints "one", "two", "three", "four", "five",

Obviously we need to strip the trailing comma from the end of this string. To do this you can use the following function.

function deleteTrailingCommas($str)
{
    return trim(preg_replace("/(.*?)((,|\s)*)$/m", "$1", $str));
}

This function uses a regular expression to match for one or more commas or spaces after the main bulk of text and before the end of the string and prints out the main bulk of text. The trailing commas are not returned.

Here is another example:

$string = '"one", , ,  , , , ,,';
echo $string;
$string = deleteTrailingCommas($string);
echo $string;

This prints out the following:

"one", , ,  , , , ,,
"one"
PHP

Comments

I didn't know the trim() function accepted a second paramter. Thanks for pointing that out :)

Philip Norton

Submitted by giHlZp8M8D on Thu, 02/17/2011 - 20:24

Permalink

Add new comment

The content of this field is kept private and will not be shown publicly.
CAPTCHA
16 + 0 =
Solve this simple math problem and enter the result. E.g. for 1+3, enter 4.
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.

Related Content

Generating Colour Palettes From Images In PHP

4th August 2024

A common web design pattern is to incorporate an image into the design of the page. This creates a tighter integration with the image and the rest of the page.

The main issue in designing a page around the image is that the colours of the page must match the image. Otherwise this creates a dissonance between the image and the styles of the site.

Read more

Validating XML Files With XML Schema Definitions In PHP

21st July 2024

XML is a useful format for configuration, data storage, and transmitting data from one system to another. As a human readable format that can be easily read by machines it quickly gained favor in lots of different systems as a mechanism for data storage.

Read more

Approximating Pi Using A Circle And A Square

26th May 2024

Pi day was a few weeks ago, but I came across this simple approximation of pi recently and decided to put together an example in PHP since it seemed pretty simple.

This approximation of pi centers around a real world example, but we can simulate this using some code.

Read more

Drawing A Parabolic Curve With Straight Lines In PHP

12th May 2024

A parabolic curve is a type of curve where every point is an equal distance from a focal point. There a number of different way to generate this sort of curve using math, but one of the simplest is to use straight lines to create the illusion of the curve.

Read more

Recreating Spotify Wrapped In PHP

17th March 2024

I quite like the end of the year report from Spotify that they call "Wrapped". This is a little application in which they tell you what your favorite artist was and what sort of genres you listened to the most during the year.

Read more