This document discusses various PHP functions categorized into different groups like: - Date Functions: date, getdate, setdate, Checkdate, time, mktime - String Functions: strtolower, strtoupper, strlen, trim, substr, strcmp etc. - Math Functions: abs, ceil, floor, round, pow, sqrt, rand - User Defined Functions: functions with arguments, default arguments, returning values - File Handling Functions: fopen, fread, fwrite, fclose to handle files - Miscellaneous Functions: define, constant, include, require, header to define constants, include files etc.

1. PHP Functions
jigar makhija

2. Date Functions
Date, getdate, setdate, Checkdate, time, mktime
<?php
$time = time();
print("Current Timestamp: ".$time);
?>
<?php
$bool = checkdate(12, 12, 2005);
if($bool){
print("Given date is valid");
}else{
print("Given date is invalid");
}
?>
DATE
<?php
$date = date("D M d Y");
print("Date: ".$date);
?>
TIME
<?php
$timestamp = mktime();
print($timestamp);
?>

3. Setting and Getting Dates
<?php
//Creating a date
$date = new DateTime();
//Setting the date
date_date_set($date, 2019, 07, 17);
print("Date: ".date_format($date, "Y/m/d"));
?>
<?php
//Date string
$date_string = "25-09-1989";
//Creating a DateTime object
$date_time_Obj = date_create($date_string);
print("Original Date: ".date_format($date_time_Obj,
"Y/m/d"));
print("n");
//Setting the date
$date = date_date_set($date_time_Obj, 2015, 11, 25 );
print("Modified Date: ".date_format($date, "Y/m/d"));
<?php
//Creating a DateTime object
$date_time_Obj = date_create("25-09-1989");
//formatting the date/time object
$format = date_format($date_time_Obj, "y-d-
m");
print("Date in yy-dd-mm format: ".$format);
?>
<?php
$info = getdate();
print_r($info);
?>

4. Variable Function
Gettype, settype, isset, unset, strval, floatval, intval, print_r
$a = 3;
echo gettype($a) . "<br>";
$b = 3.2;
echo gettype($b) . "<br>";
$a = array("red", "green", "blue");
print_r($a);
echo "<br>";
$b = array("Peter"=>"35", "Ben"=>"37",
"Joe"=>"43");
print_r($b);
<?php
$a = "32"; // string
settype($a, "integer"); // $a is now integer
$b = 32; // integer
settype($b, "string"); // $b is now string
$c = true; // boolean
settype($c, "integer"); // $c is now integer (1)
?>
$a = 0;
// True because $a is set
if (isset($a)) {
echo "Variable 'a' is set.<br>";
}

5. Variable Function
Gettype, settype, isset, unset, strval, floatval, intval, print_r
$a = "Hello world!";
echo "The value of variable 'a' before unset: " . $a . "<br>";
unset($a);
echo "The value of variable 'a' after unset: " . $a;
?>
$b = 3.2;
echo intval($b) . "<br>";
$c = "32.5";
echo intval($c) . "<br>";
$b = "1234.56789Hello";
echo floatval($b) . "<br>";
$c = "Hello1234.56789";
echo floatval($c) . "<br>";
$a = "1234.56789";
echo doubleval($a) .
"<br>";
$b = "1234.56789Hello";
echo doubleval($b) .
"<br>";
$d = "Hello1234.56789";
echo strval($d) . "<br>";
$e = 1234;
echo strval($e) . "<br>";

6. String Function
Chr, ord, strtolower, strtoupper, strlen, ltrim, rtrim trim, substr, strcmp,
strcasecmp, strops,strrpos, strstr, stristr, str_replace, strrev, echo, print
• echo():Outputs one or more strings
• print():Outputs one or more strings
• Chr(): Returns a character from a specified ASCII value
• ord():Returns the ASCII value of the first character of a string
• strtolower(): Converts a string to lowercase letters
• strtoupper():Converts a string to uppercase letters
• strlen():Returns the length of a string
• rtrim ():Removes whitespace or other characters from the right
side of a string
• ltrim():Removes whitespace or other characters from the left
side of a string
• trim():Removes whitespace or other characters from both sides of a string

7. String Function
Chr, ord, strtolower, strtoupper, strlen, ltrim, rtrim trim, substr, strcmp,
strcasecmp, strops,strrpos, strstr, stristr, str_replace, strrev, echo, print
– strcmp():Compares two strings (case-sensitive)
– strcasecmp():Compares two strings (case-insensitive)
– strpos():Returns the position of the first occurrence of a string inside
another string (case-sensitive)
– strrpos():Finds the position of the last occurrence of a string inside
another string (case-sensitive)
– strstr():Finds the first occurrence of a string inside another string
(case-sensitive)
– stristr():Finds the first occurrence of a string inside another string
(case-insensitive)
– str_replace():Replaces some characters in a string (case-sensitive)
– strrev():Reverses a string

8. Math Function
Abs, ceil, floor, round, fmod, min, max, pow, sqrt, rand
<?php
echo (abs(-7)."<br/>"); // 7
(integer)
echo (abs(7)."<br/>"); //7 (integer)
echo (abs(-7.2)."<br/>"); //7.2
(float/double)
?>
<?php
echo (ceil(3.3)."<br/>");// 4
echo (ceil(7.333)."<br/>");// 8
echo (ceil(-4.8)."<br/>");// -4
?>
<?php
echo (floor(3.3)."<br/>");// 3
echo (floor(7.333)."<br/>");//
7
echo (floor(-4.8)."<br/>");// -5
?>
<?php
echo (sqrt(16)."<br/>");// 4
echo (sqrt(25)."<br/>");// 5
echo (sqrt(7)."<br/>");//
2.6457513110646
?>
<?php
$num=pow(3, 2);
echo $num;
?>
echo "using round() function : ".(round(3.96754,2)); echo "Random number b/w 10-100:
".(rand(10,100));
$x = 5.7;
$y = 1.3;
echo "Your Given Nos is : x=5.7, y=1.3";
echo "<br>"."By using 'fmod()' function your
value is:".fmod($x, $y);
$num=min(4,14,3,5,14.2); $num=max(4,14,3,5,14.2);

9. User Define Function
argument function, default argument, variable function, return
function
function functionname(){
//code to be executed
}
<?php
function sayHello(){
echo "Hello PHP Function";
}
sayHello();//calling function
?>
function sayHello($name){
echo "Hello $name<br/>";
}
sayHello("Sonoo");
function sayHello($name,$age){
echo "Hello $name, you are $age years
old<br/>";
}
sayHello("Sonoo",27);
function adder(&$str2)
{
$str2 .= 'Call By Reference';
}
$str = 'Hello ';
adder($str);
echo $str;
function
sayHello($name="Sonoo"){
echo "Hello $name<br/>";
}
sayHello("Rajesh");
sayHello();
function cube($n){
return $n*$n*$n;
}
echo "Cube of 3 is:
".cube(3);
//RECURSIVE FUNCTIONS
<?php
function display($number) {
if($number<=5){
echo "$number <br/>";
display($number+1);
}
}
display(1);

10. Variable Length Argument Function:
func_num_args, func_get_arg, func_get_args
function combined() {
$num_arg = func_num_args();
echo "Number of arguments: " .$num_arg . "n";
}
combined('A', 'B', 'C');
<?php
function printValue($value) {
// Update value variable
$value = "The value is: " . $value;
// Print the value of the first argument
echo func_get_arg(0);
}
// Run function
printValue(123);
?>
<?php
function combined() {
$num_arg = func_num_args();
if($num_arg > 0) {
$arg_list = func_get_args();
for ($i = 0; $i < $num_arg; $i++) {
echo "Argument $i is: " . $arg_list[$i] . "n";
}
}
}
combined('A', 'B', 'C');
?>

11. Count, list, in_array, current, next, previous, end, each, sort, rsort,
asort,
arsort, array_merge, array_reverse
$a[0] = 1;
$a[1] = 3;
$a[2] = 5;
$result = count($a);
print($result);
$transport = array('foot', 'bike', 'car', 'plane');
$mode = current($transport);
print "$mode <br />";
$mode = next($transport);
print "$mode <br />";
$mode = current($transport);
print "$mode <br />";
$mode = prev($transport);
print "$mode <br />";
$mode = end($transport);
print "$mode <br />";
$mode = current($transport);
print "$mode <br />";
$transport = array('foot', 'bike',
'car', 'plane');
$key_value = each($transport);
print_r($key_value);
print "<br />";
$key_value = each($transport);
print_r($key_value);
print "<br />";
$key_value = each($transport);
print_r($key_value);
$fruit = array("mango","apple","banana");
list($a, $b, $c) = $fruit;
echo "I have several fruits, a $a, a $b, and
a $c.";
$input =
array("a"=>"banan
a","b"=>"mango","c
"=>"orange");
print_r(array_rever
se($input));

12. Count, list, in_array, current, next, previous, end, each, sort, rsort,
asort,
arsort, array_merge, array_reverse
$mobile_os = array("Mac", "android", "java",
"Linux");
if (in_array("java", $mobile_os)) {
echo "Got java";
}
<?php
$input = array("d"=>"lemon", "a"=>"orange", "b"=>"banana"
);
rsort($input);
print_r($input);
?>
<?php
$input = array("d"=>"lemon", "a"=>"orange",
"b"=>"banana" );
sort($input);
print_r($input);
?>
<?php
$fruits = array("d"=>"lemon", "a"=>"orange",
"b"=>"banana" );
arsort($fruits);
print_r($fruits);
?>
<?php
$fruits = array("d"=>"lemon", "a"=>"orange", "b"=>"banana"
);
asort($fruits);
print_r($fruits);
?>
$input =
array("a"=>"Horse","b"=>"Cat","c"=>"Dog");
$input1 =
array("d"=>"Cow","a"=>"Cat","e"=>"elephant");
print_r(array_merge($input,$input1));

13. Miscellaneous Function
define, constant, include, require, header, die
<?php
define("GREETING","Hello you! How are you today?");
echo constant("GREETING");
?>
<?php
$site = "https://www.w3schools.com/";
fopen($site,"r")
or die("Unable to connect to $site");
?>
<?php
include("menu.html"); ?>
<?php
require("menu.html"); ?>
Both include and require are same. But if the file is missing or inclusion fails, include allows the
script to continue but require halts the script producing a fatal E_COMPILE_ERROR level error.
define() function to create a constant.
<?php
define("MESSAGE","Hello JavaTpoint PHP");
echo MESSAGE;
?>
define("MESSAGE","Hello JavaTpoint PHP",true);//not
case sensitive
The header() is a pre-defined network function of PHP, which sends a raw HTTP header to a client.
void header (string $header, boolean $replace = TRUE, int $http_response_code)

14. File handling Function:
fopen, fread, fwrite, fclose, file_exists, is_readable, is_writable, fgets, fgetc, file, file_get_contents,
filejutcontents, ftell, fseek, rewind, copy, unlink, rename, move upload file
<?php
$handle = fopen("c:folderfile.txt", "r");
?>
<?php
fclose($handle);
?>
<?php
$filename = "c:myfile.txt";
$handle = fopen($filename, "r");//open file in read
mode
$contents = fread($handle,
filesize($filename));//read file
echo $contents;//printing data of file
fclose($handle);//close file
?>
<?php
$fp = fopen('data.txt', 'w');//open file in write mode
fwrite($fp, 'hello ');
fwrite($fp, 'php file');
fclose($fp);
echo "File written successfully";
?>
fread(file_pointer, length)
echo fread($file_pointer, "7");
echo fgets($file);
if (file_exists($file_pointer)) {
echo "The file $file_pointer exists";
}
if (is_readable($myfile))
{
echo '$myfile is readable';
}

15. File handling Function:
fopen, fread, fwrite, fclose, file_exists, is_readable, is_writable, fgets, fgetc, file, file_get_contents,
filejutcontents, ftell, fseek, rewind, copy, unlink, rename, move upload file
$myfile = fopen("gfg.txt", "w");
echo fwrite($myfile, "Hello!");
fclose($myfile);
$myfile = fopen("gfg.txt", "r");
echo ftell($myfile);
fseek($myfile, "36");
echo ftell($myfile);
$myfile = fopen("gfg.txt", "r+");
fwrite($myfile, 'geeksforgeeks');
rewind($myfile);
fwrite($myfile, 'portal');
rewind($myfile);
echo fread($myfile, filesize("gfg.txt"));
fclose($myfile);
$srcfile = '/user01/Desktop/admin/gfg.txt';
$destfile = 'user01/Desktop/admin/geeksforgeeks.txt';
echo copy($srcfile, $destfilefile);
rename( $old_name, $new_name) ;
unlink('data.txt');
echo "File deleted successfully";
// file is opened using fopen() function
$my_file = fopen("gfg.txt", "rw");
// Prints a single character from the
// opened file pointer
echo fgetc($my_file);