Variables in PHP
variables in php
declaring variables in php is very simple .its more easier then java and c++ to declare variable•PHP variables must begin with a “$” sign
ie $x , $y•Case-sensitive
($Foo != $foo != $fOo)
•Global and locally-scoped variables
–Global variables can be used anywhere–Local variables restricted to a function or class
•Certain variable names reserved by PHP
–Form variables ($_POST, $_GET)–Server variables ($_SERVER)
–Etc.
•PHP is a loosely typed language
–In PHP, a variable does not need to be declared before adding a value to itExample code
[code start]
<?php
$foo =
25; // Numerical variable
$bar = “Hello”; // String variable
$bar = “Hello”; // String variable
$foo =
($foo *
7); // Multiplies foo
by 7
$bar = ($bar * 7); // Invalid expression
$bar = ($bar * 7); // Invalid expression
?>
[code end]
Echo in php
•The PHP command ‘echo’
is used to output the parameters passed to it–The typical usage for this is to send data to the client’s web-browser
•Syntax
–void echo (string arg1 [, string argn...])
–In practice, arguments are not passed in parentheses since echo is a language construct rather than an actual function
–In practice, arguments are not passed in parentheses since echo is a language construct rather than an actual function
Example:
[code start]
<html>
<body>
<?php
echo "Hello
World";
?>
<br />
<?php
$txt="Hello
World";
echo $txt;
?>
</body>
</html>
[code end]
Example2:
[code start]
<?php
$foo =
25; // Numerical variable
$bar = “Hello”; // String variable
$bar = “Hello”; // String variable
echo
$bar; // Outputs Hello
echo $foo,$bar; // Outputs 25Hello
echo “5x5=”,$foo; //
Outputs 5x5=25
echo “5x5=$foo”; //
Outputs 5x5=25
echo ‘5x5=$foo’; // Outputs 5x5=$foo
echo ‘5x5=$foo’; // Outputs 5x5=$foo
?>
[code start]
•Notice how echo ‘5x5=$foo’ outputs $foo rather than replacing it with 25
•Strings in single quotes (‘ ’) are not interpreted or evaluated by PHP
•This is true for both variables and character escape-sequences (such as “\n” or “\\”)
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