Q:what is number_format.

number_format — Format a number with grouped thousands

Q:What is unset.

unset — Unset a given variable

Q: What is nl2b.

nl2br — Inserts HTML line breaks before all newlines in a string

<?php
echo nl2br("Welcome\r\nThis is my HTML document", false);
?>

Welcome<br>

This is my HTML document

Q: How can encrypt and decript in mysql .

AES_DECRYPT() Decrypt using AES
AES_ENCRYPT() Encrypt using AES

$query = "insert into member (spid,uname,pss) values ('$xyz','$username',aes_encrypt('$password','password'))";

$query = "select uname,aes_decrypt(pss,'password') as password from member where spid='$xyz'";

Q:How can get ip address using php

$ip=@$REMOTE_ADDR;
echo "<b>IP Address= $ip</b>";

 IP address= 1.23.174.67

$ip=$_SERVER['REMOTE_ADDR'];

Q: How can get days between two date in php

$days = (strtotime("2005-11-20") - strtotime(date("Y-m-d"))) / (60 * 60 * 24);

Q: How can find out unique number array.

array_unique — Removes duplicate values from an array.

<?php
$input = array("a" => "green", "red", "b" => "green", "blue", "red");
$result = array_unique($input);
print_r($result);
?>

Q: How can reverse strings in php

strrev — Reverse a string

<?php
echo strrev("Hello world!"); // outputs "!dlrow olleH"
?>

Q: how can shorting array in php?

Q: how can shorting array .

Or

Q: What is shorting array 

sort — Sort an array

<?php
$fruits = array("lemon", "orange", "banana", "apple");
sort($fruits);
foreach ($fruits as $key => $val) {
    echo "fruits[" . $key . "] = " . $val . "\n";
}
?>

fruits[0] = apple

fruits[1] = banana

fruits[2] = lemon

fruits[3] = orange

arsort — Sort an array in reverse order and maintain index association

<?php
$fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple");
arsort($fruits);
foreach ($fruits as $key => $val) {
    echo "$key = $val\n";
}
?>

a = orange

d = lemon

b = banana

c = apple

 next — Advance the internal array pointer of an array

<?php
$transport = array('foot', 'bike', 'car', 'plane');
$mode = current($transport); // $mode = 'foot';
$mode = next($transport);    // $mode = 'bike';
$mode = next($transport);    // $mode = 'car';
$mode = prev($transport);    // $mode = 'bike';
$mode = end($transport);     // $mode = 'plane';
?>

Q: what is func_num_args() and func_get_arg() in php ?

func_num_args — Returns the number of arguments passed to the function.

<?php
function foo()
{
    $numargs = func_num_args();
    echo "Number of arguments: $numargs\n";
}
foo(1, 2, 3);   
?>