No need to elaborate much on this one. Here are ten very useful functions for manipulating strings. Some are very simple and straightforward, but are still very useful.
I would normally use these in class called something like Common_Strings, and make each function static but I’ll just provide them here as functions for you to use as you please.
1. Replace Last Occurrence of a String
/**
* Replace the last occurrence of a string.
*
* @param string $search
* @param string $replace
* @param string $subject
* @return string
*/
function strReplaceLast ( $search, $replace, $subject ) {
$lenOfSearch = strlen( $search );
$posOfSearch = strrpos( $subject, $search );
return substr_replace( $subject, $replace, $posOfSearch, $lenOfSearch );
}
2. Strip All Non-Alpha Numeric Characters and Spaces
/**
* Remove all characters except letters, numbers, and spaces.
*
* @param string $string
* @return string
*/
function stripNonAlphaNumericSpaces( $string ) {
return preg_replace( "/[^a-z0-9 ]/i", "", $string );
}
3. Strip All Non-Alpha Numeric Characters
/**
* Remove all characters except letters and numbers.
*
* @param string $string
* @return string
*/
function stripNonAlphaNumeric( $string ) {
return preg_replace( "/[^a-z0-9]/i", "", $string );
}
4. Remove All Non-Numeric Characters
/**
* Remove all characters except numbers.
*
* @param string $string
* @return string
*/
function stripNonNumeric( $string ) {
return preg_replace( "/[^0-9]/", "", $string );
}
5. Remove All Non-Alpha Characters
/**
* Remove all characters except letters.
*
* @param string $string
* @return string
*/
function stripNonAlpha( $string ) {
return preg_replace( "/[^a-z]/i", "", $string );
}
6. Remove All Excess White-Space
/**
* Transform two or more spaces into just one space.
*
* @param string $string
* @return string
*/
function stripExcessWhitespace( $string ) {
return preg_replace( '/ +/', ' ', $string );
}
7. Format a String for a URL Slug
/**
* Format a string so it can be used for a URL slug
*
* @param string $string
* @return string
*/
function formatForUrl( $string ) {
$string = stripNonAlphNumericSpaces( trim( strtolower( $string ) ) );
return str_replace( " ", "-", stripExcessWhitespace( $string ) );
}
8. Format an URL Slug into a Human Readable String
/**
* Format a slug into human readable string
*
* @param string $string
* @return string
*/
function formatFromUrl( $string ) {
return str_replace( "-", " ", trim( strtolower( $string ) ) );
}
9. Get Unique Characters from a String
/**
* Get an array of unique characters used in a string. This should also work with multibyte characters.
*
* @param string $string
* @return mixed
*/
function getUniqueChars( $string, $returnAsArray=true ) {
$unique = array_unique( preg_split( '/(?<!^)(?!$)/u', $string ) );
if ( empty( $returnAsArray ) ) {
$unique = implode( "", $unique );
}
return $unique;
}
10. Generate a Random String
/**
* Generate a random string of specified length from a set of specified characters
*
* @param integer $size Default size is 30 characters.
* @param string $chars The characters to use for randomization.
*/
function randomString( $size=30, $chars="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" ) {
$string = "";
$length = strlen( $chars );
for( $i=0; $i < $size; $i++ ) {
$string .= $chars{ rand( 0, $length ) };
}
return $string;
}