Skip to content
Related Articles

Related Articles

PHP | eval() Function
  • Last Updated : 20 Jun, 2018

The eval() function in PHP is an inbuilt function that evaluates a string as PHP code.

Syntax:

eval( $string )

Parameters: This function accepts a single parameter as shown in above syntax and and described below.

  • $string: It must consist of a valid PHP code to be evaluated but should not contain opening and closing PHP tags.

Note: All statements must be properly terminated using a semicolon. For example, initializing the string as ‘echo “Geeks for Geeks”‘ will cause a parse error. In order to rectify, need to initialize as ‘echo “Geeks for Geeks”;’.

Return Value: Returns NULL unless a return statement is called in the input string containing PHP code. Then the value is returned. In case of a parse error in the input string, the function returns FALSE.



Examples:

Input : $age = 20; $str = "I am $age years old"
        eval("\$str = \"$str\";");
Output : I am 20 years old

Input : $str = 'echo "Geeks for Geeks";';
        echo eval($str). "\n";
Output : Geeks for Geeks

Below programs illustrate the use of eval() function:

Program 1:




<?php
  
$age = 20;
$str = 'My age is $age';
echo $str. "\n";
  
eval("\$str = \"$str\";");
echo $str. "\n";
?>


Output:

My age is $age
My age is 20

Program 2:




<?php
  
$str = 'echo "Geeks for Geeks";';
echo eval($str). "\n";
?>


Output:

Geeks for Geeks

Reference : http://php.net/manual/en/function.eval.php

My Personal Notes arrow_drop_up
Recommended Articles
Page :