PHP String Functions

The strstr() function and stristr() function can find the first occurrence of a substring (second parameter) inside another string (first parameter), and return all characters from the first occurrence till the end of the string.

The substr() function returns a part of a string.

The strlen() function returns the length of a given string. It returns 0 if the string is empty.

Many times, the strings have extra spaces that need to be removed. For example, you might want to replace multiple spaces with a single space or you might want to get rid of all the whitespace in a string. Similarly, you might be planning on stripping all the whitespace from either the left or the right end of a string.

The explode() function in PHP is used to split a string into multiple strings based on the specified delimiter. It is similar to the split function in Perl.

The preg_match() function searches a string for a specific pattern, returning TRUE if it exists and FALSE otherwise.

All these functions are used to manipulate strings. They are part of the PHP core, so you don't have to install anything to use these functions.