PHP Strings

I was sent an email the other day that contained some text were the start and end letter of each word were left alone, but the middle of each word was randomized. The weird part was that the text was still readable, which is due to the way in which the brain processes words.

Use the following function to filter out words from user input. It works by having a pre-set array of words that are to be excluded, this array is then looped through and each item is used to replace any instances of that word within the text. The regular expression uses the \b character class, which stands for any word boundary. This way you don't get the middle of words being filtered out when they are not meant to be.

I found a little problem today when processing a bit of text from a non-english site. I found that the text was being loaded properly, but because it was in UTF-8 encoding PHP couldn't use htmlspecialchars() or apply get_html_translation_table() to the string to properly encode the foreign characters. These methods just don't have any effect. This is because PHP (before version 5.2.x) doesn't natively support unicode character encoding and is therefore not able to translate characters in UTF-8 format.

Use the following code to split a string into an array of characters.

The PHP function preg_replace() has powerful functionality in its own right, but extra depth can be added with the inclusion of the e modifier. Take the following bit of code, which just picks out the letters of a string and replaces them with the letter X.

Getting users to enter a list of items is a normal practice, but getting users to do it properly is sometimes a challenge in itself. Some users will put spaces in between the commas, others will not, some will even put a trailing comma at the end of the list.

Here is some code that can be used to clear up a comma separated list using some simple regular expressions. It works using the preg_replace() function, and by passing this function an array of options patterns and an array of replacements.

There are many ways to find a string within another string using PHP, but which one is the quickest? I did the same sort of test that I have done with double or single quotes and downloading web pages with a few of the string matching functions available in PHP.

I first generated a very long string that could be used in the string matching functions. The following for loop generates a string containing "iteration 0 and iteration 1 and iteration 2..." right up until "iteration 4999 and".