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Created by jinx on May 03, 2011 11:43:26    Last update: May 03, 2011 11:43:26
The PHP function strval returns the string value of a variable. It does the same thing as casting a variable to string, or automatic conversion where string is expected. Conversion rules: Type String Value Boolean TRUE '1' Boolean FALSE '' (empty string) integer of float string representing the number Array The string 'Array' Object Result of __toString() if defined, error otherwise Resource 'Resource id #n' , where n is a number assigned to the resource. NULL '' (empty string) Example: <?php set_error_handler(function($errno, $errst... Results: bool(true) --------------------- strval: '1'...
Created by jinx on April 29, 2011 15:03:10    Last update: April 29, 2011 15:04:02
The PHP function is_callable verifies that a variable can be invoked as a function. Example: <?php define('F', 'f'); function... Output: var_dump: string(1) "f" is_callable: 1 Calla...
Created by jinx on April 28, 2011 20:52:45    Last update: April 29, 2011 13:27:31
This is normally a syntax error just before some variable. Try some of these: Missing operator before a variable: <?php $a = 'ab'; echo('Missing conca... Missing semicolon at end of line: <?php echo('Missing semicolon at end of lin... Missing ( and ) in for loop: <?php foreach $a as $i { echo "$i\n"; ... Missing keyword before class variable: <?php class A { // should be var $a; ...
Created by jinx on April 26, 2011 21:52:10    Last update: April 26, 2011 21:52:10
PHP offers several ways to check the class type of an object instance at runtime: instanceof operator, is_a function, get_class function. Example: <?php class A { } class B { } ...
Created by jinx on April 25, 2011 12:43:40    Last update: April 25, 2011 12:43:40
Use the PHP function method_exists to check if the class or object has a certain method. It returns TRUE if the method exists (even when the value of the property is NULL), FALSE if the method does not exist. Example: <?php class A { var $p = 'A property'; ... Outputs: Class A has method f1: bool(true) Object $a has... Also note that C++-like method overloading does not exist in PHP. Thus there's no ambiguity about which version of the method exists, i.e., with no argument, with one argument... etc. The following code generates Fatal error: <?php class A { var $p = 'A property'; ...
Created by jinx on April 25, 2011 11:50:09    Last update: April 25, 2011 11:51:53
Use the PHP function property_exists to check if the class or object has a certain property. It returns TRUE if the property exists (even when the value of the property is NULL), FALSE if the property does not exist, or NULL in case of an error. Example: <?php class A { var $p = 'A property'; ... Outputs: Class A has property $p: bool(false) Class A ha...
Created by Dr. Xi on January 30, 2009 16:57:12    Last update: January 30, 2009 17:25:36
The scriptable attribute defaults to false . However, even when you set it to true , there is a time delay between when the applet is loaded and when it becomes scriptable . The following code may fail: <html><body> <object classid="clsid:8AD9C840-04... You need to wrap the JavaScript like this: <script language="JavaScript" type="text/javascrip...
Created by Dr. Xi on December 12, 2007 20:30:01    Last update: December 12, 2007 20:32:23
This is a script to tail a log file through the web browser. It uses AJAX, apache web server, mod_python, UNIX utilities tail (requires the --lines switch) and wc . The log file may reside on the web server or any other host accessible from the web server through SSH. Although it's written in python, it should be easy to port to other languages such as Perl. Apache httpd.conf : LoadModule python_module modules/mod_python.so ... Python script: import time, os from os.path import basename ...