String manipulation functions
strlen(): Returns the length of a string.
$str = "hello";
echo strtoupper($str); // Output: HELLO
strtoupper(): Converts a string to uppercase.
$str = "hello";
echo strtoupper($str); // Output: HELLO
strtolower(): Converts a string to lowercase.
$str = "WORLD";
echo strtolower($str); // Output: world
substr(): Extracts a portion of a string based on a starting position and length.
$str = "Hello, world!";
echo substr($str, 7, 5); // Output: world
Number manipulation functions
intval(): Converts a value to an integer.
$num = 10.5;
echo intval($num); // Output: 10
loatval(): Converts a value to a float.
$num = "3.14";
echo floatval($num); // Output: 3.14
number_format(): Formats a number with thousands separators.
$num = 1000;
echo number_format($num); // Output: 1,000
Array manipulation functions
count(): Counts the number of elements in an array.
$arr = [1, 2, 3, 4, 5];
echo count($arr); // Output: 5
array_push(): Adds an element to the end of an array.
$arr = [1, 2, 3];
array_push($arr, 4);
print_r($arr); // Output: [1, 2, 3, 4]
array_pop(): Removes and returns the last element of an array.
$arr = [1, 2, 3, 4];
$lastElement = array_pop($arr);
echo $lastElement; // Output: 4
These are just a few examples of commonly used functions in PHP. There are many more functions available for various tasks. You can explore the PHP documentation for more details on different functions and their usage.