Htaccess    html   Php    javascript   Asp   css    maths  Past Questions  Practice Tests Online

eval function syntax tag tutorial 2013 Donate at flattr Flattr this





Alert! Connect with 10,000 Chating Online. Join Now

Php eval () function

Write your php code

 
<?php ?>

Php Result


Your code below



(PHP 3, PHP 4, PHP 5 )

eval -- Evaluate a string as PHP code

Syntax

mixed eval ( string code_str )

eval() evaluates the string given in code_str as PHP code. Among other things, this can be useful for storing code in a database text field for later execution.

There are some factors to keep in mind when using eval(). Remember that the string passed must be valid PHP code, including things like terminating statements with a semicolon so the parser doesn't die on the line after the eval(), and properly escaping things in code_str.

Also remember that variables given values under eval() will retain these values in the main script afterwards.

A return statement will terminate the evaluation of the string immediately. As of PHP 4, eval() returns NULL unless return is called in the evaluated code, in which case the value passed to return is returned. In case of a parse error in the evaluated code, eval() returns FALSE. In case of a fatal error in the evaluated code, the whole script exits. In PHP 3, eval() does not return a value.

Example 1. eval() example - simple text merge

<?php
$string
= 'cup';
$name = 'coffee';
$str = 'This is a $string with my $name in it.';
echo
$str. "\n";
eval(
"\$str = \"$str\";");
echo
$str. "\n";
?>

The above example will output:

This is a $string with my $name in it.
This is a cup with my coffee in it.

Tip: As with anything that outputs its result directly to the browser, you can use the output-control functions to capture the output of this function, and save it in a string (for example).

See also call_user_func().

Php eval Function syntax tag

eval php code on this is provided for your study purpose, it will guide you to know how create and design a website using php. use it to practice and train your self online



Php eval syntax tutorial

php tutorial guide and code design are for easy learning and programming. The code practice section provided at the top is for practising of this syntax. Use the code section up to practice your php programming online. Learning php is very easy, all you need is to use the examples on this site and practice them to perfect your skills.


Function index

Variables

Expressions

Operators

Control-Structures

Cookies

Array

Date & Time

Directory function

File

Image

Operators

Form data handling

Mathematics operators

Mail

Php Mysql

Network Functions

Strings

php tutorial guides,functions, classes, code examples and tags for creating simple dynamic site to mysql database driven sites
 
 
Htaccess    html   Php    javascript   Asp   css    maths  Past Questions  Practice Tests Online