PHP has a set of built-in functions that you can use to modify strings.
Upper Case
Example
The strtoupper() function returns the string in upper case:
$x = "Hello World!";
echo strtoupper($x);
Lower Case
Example
The strtolower() function returns the string in lower case:
$x = "Hello World!";
echo strtolower($x);
Replace String
The PHP str_replace() function replaces some characters with some other characters in a string.
Example
Replace the text “World” with “Dolly”:
$x = "Hello World!";
echo str_replace("World", "Dolly", $x);
Reverse a String
The PHP strrev() function reverses a string.
Example
Reverse the string “Hello World!”:
$x = "Hello World!";
echo strrev($x);
Remove Whitespace
Whitespace is the space before and/or after the actual text, and very often you want to remove this space.
Example
The trim() removes any whitespace from the beginning or the end:
$x = " Hello World! ";
echo trim($x);
Learn more in our trim() Function Reference.
Convert String into Array
The PHP explode() function splits a string into an array.
The first parameter of the explode() function represents the “separator”. The “separator” specifies where to split the string.
Note: The separator is required.
Example
Split the string into an array. Use the space character as separator:
$x = "Hello World!";
$y = explode(" ", $x);
//Use the print_r() function to display the result:
print_r($y);
/*
Result:
Array ( [0] => Hello [1] => World! )
*/