Collection of useful PHP functions and code snippets.
function identity(mixed $arg): mixed {
return $arg;
}
$interpolate = "identity";
echo "<input value='{$interpolate(1 + 1 * random_int())}' />";See Casting.php
/**
* Checks if a folder exist and return canonicalized absolute pathname (sort version)
* @param string $folder the path being checked.
* @return mixed returns the canonicalized absolute pathname on success otherwise FALSE is returned
*/
function folder_exist(string $folder): string|false
{
// Get canonicalized absolute pathname
$path = realpath($folder);
// If it exist, check if it's a directory
return ($path !== false AND is_dir($path)) ? $path : false;
}See JSON2Class.php
// Source - https://stackoverflow.com/a/70378792
// Posted by dearsina, modified by community. See post 'Timeline' for change history
// Retrieved 2026-01-07, License - CC BY-SA 4.0
/**
* Over-engineered solution to most capitalisation issues.
*
* @author https://stackoverflow.com/users/429071/dearsina
* @version 1.0
*/
class str {
/**
* Words or abbreviations that should always be all uppercase
*/
const ALL_UPPERCASE = [
"UK",
"VAT",
];
/**
* Words or abbreviations that should always be all lowercase
*/
const ALL_LOWERCASE = [
"and",
"as",
"by",
"in",
"of",
"or",
"to",
];
/**
* Honorifics that only contain consonants.
*
*/
const CONSONANT_ONLY_HONORIFICS = [
# English
"Mr",
"Mrs",
"Ms",
"Dr",
"Br",
"Sr",
"Fr",
"Pr",
"St",
# Afrikaans
"Mnr",
];
/**
* Surname prefixes that should be lowercase,
* unless not following another word (firstname).
*/
const SURNAME_PREFIXES = [
"de la",
"de las",
"van de",
"van der",
"vit de",
"von",
"van",
"del",
"der",
];
/**
* Capitalises every (appropriate) word in a given string.
*
* @param string|null $string
*
* @return string|null
*/
public static function capitalise(?string $string): ?string
{
if(!$string){
return $string;
}
# Strip away multi-spaces
$string = preg_replace("/\s{2,}/", " ", $string);
# Ensure there is always a space after a comma
$string = preg_replace("/,([^\s])/", ", $1", $string);
# A word is anything separated by spaces or a dash
$string = preg_replace_callback("/([^\s\-\.]+)/", function($matches){
# Make the word lowercase
$word = mb_strtolower($matches[1]);
# If the word needs to be all lowercase
if(in_array($word, self::ALL_LOWERCASE)){
return strtolower($word);
}
# If the word needs to be all uppercase
if(in_array(mb_strtoupper($word), self::ALL_UPPERCASE)){
return strtoupper($word);
}
# Create a version without diacritics
$transliterator = \Transliterator::createFromRules(':: Any-Latin; :: Latin-ASCII; :: NFD; :: [:Nonspacing Mark:] Remove; :: Lower(); :: NFC;', \Transliterator::FORWARD);
$ascii_word = $transliterator->transliterate($word);
# If the word contains non-alpha characters (numbers, &, etc), with exceptions (comma, '), assume it's an abbreviation
if(preg_match("/[^a-z,']/i", $ascii_word)){
return strtoupper($word);
}
# If the word doesn't contain any vowels, assume it's an abbreviation
if(!preg_match("/[aeiouy]/i", $ascii_word)){
# Unless the word is an honorific
if(!in_array(ucfirst($word), self::CONSONANT_ONLY_HONORIFICS)){
return strtoupper($word);
}
}
# If the word contains two of the same vowel and is 3 characters or fewer, assume it's an abbreviation
if(strlen($word) <= 3 && preg_match("/([aeiouy])\1/", $word)){
return strtoupper($word);
}
# Ensure O'Connor, L'Oreal, etc, are double capitalised, with exceptions (d')
if(preg_match("/\b([a-z]')(\w+)\b/i", $word, $match)){
# Some prefixes (like d') are not capitalised
if(in_array($match[1], ["d'"])){
return $match[1] . ucfirst($match[2]);
}
# Otherwise, everything is capitalised
return strtoupper($match[1]) . ucfirst($match[2]);
}
# Otherwise, return the word with the first letter (only) capitalised
return ucfirst($word);
//The most common outcome
}, $string);
# Cater for the Mc prefix
$pattern = "/(Mc)([b-df-hj-np-tv-z])/";
//Mc followed by a consonant
$string = preg_replace_callback($pattern, function($matches){
return "Mc" . ucfirst($matches[2]);
}, $string);
# Cater for Roman numerals (need to be in all caps)
$pattern = "/\b((?<![MDCLXVI])(?=[MDCLXVI])M{0,3}(?:C[MD]|D?C{0,3})(?:X[CL]|L?X{0,3})(?:I[XV]|V?I{0,3}))\b/i";
$string = preg_replace_callback($pattern, function($matches){
return strtoupper($matches[1]);
}, $string);
# Cater for surname prefixes (must be after the Roman numerals)
$pattern = "/\b (".implode("|", self::SURNAME_PREFIXES).") \b/i";
//A surname prefix, bookended by words
$string = preg_replace_callback($pattern, function($matches){
return strtolower(" {$matches[1]} ");
}, $string);
# Cater for ordinal numbers
$pattern = "/\b(\d+(?:st|nd|rd|th))\b/i";
//A number suffixed with an ordinal
$string = preg_replace_callback($pattern, function($matches){
return strtolower($matches[1]);
}, $string);
# And we're done done
return $string;
}
}