I need to replicate it for a Word button link to go next to it. If you need to consider the empty string as an acceptable return value, you must go the classical 'if' way.This code gives me the PDF button link. NOTE: '' (the empty string) is evaluated as a FALSE logical operand, so make sure that the empty string is not an acceptable value from my_function(). This is almost the same as the solution from, except that his solution (parenthesis and double pipe) doesn't take advantage of the 'or' low precedence. * if the left side is none of the previously mentioned values, the logical operation ends and $v keeps the return value from my_function() * if the left side is false, null, 0, or an empty string, the right side must be evaluated and, again, because 'or' has low precedence, $v is assigned the string 'default'

It works because, first, $v is assigned the return value from my_function(), then this value is evaluated as a part of a logical operation: To assign default value in variable assignation, the simpliest solution to me is: For example fruit() will be called twice:īut since «since PHP 5.3, it is possible to leave out the middle part of the ternary operator» ( ), now you can code like this:īut remember that a non-empty string '0' evaluates to FALSE! Instead, you have to use the '?:' operator:īut $fruit will be evaluated twice, which is not desirable. If you want to use the '||' operator to set a default value, like this: The point of being a good programmer is writting code that is easy to understand (comment your code when necessary!), easy to maintain and with high efficiency, among other things. And even if you get to learn it remember that being a good programmer is not showing you can do code with fewer words. If you find it hard to remember operators precedence you can always use parenthesys - '(' and ')'. '||' has greater precedence than 'or' and than '=', whereas 'or' doesnt have greater precedence than '=', so

$f = false or true // $f will be assigned to false If necessary, I wanted to give further explanation on this and say that when we write:

Worth reading for people learning about php and programming: (adding extras to get highlighted code)Ībout the following example in this page manual: I wrote a little helper method that I put in a function dump library (here presented as a bare function):īut more importantly, instead of writing: In order to kind of emulate the way javascript assigns the first non-false value in an expression such as this: Getting Started Introduction A simple tutorial Language Reference Basic syntax Types Variables Constants Expressions Operators Control Structures Functions Classes and Objects Namespaces Enumerations Errors Exceptions Fibers Generators Attributes References Explained Predefined Variables Predefined Exceptions Predefined Interfaces and Classes Predefined Attributes Context options and parameters Supported Protocols and Wrappers Security Introduction General considerations Installed as CGI binary Installed as an Apache module Session Security Filesystem Security Database Security Error Reporting User Submitted Data Hiding PHP Keeping Current Features HTTP authentication with PHP Cookies Sessions Dealing with XForms Handling file uploads Using remote files Connection handling Persistent Database Connections Command line usage Garbage Collection DTrace Dynamic Tracing Function Reference Affecting PHP's Behaviour Audio Formats Manipulation Authentication Services Command Line Specific Extensions Compression and Archive Extensions Cryptography Extensions Database Extensions Date and Time Related Extensions File System Related Extensions Human Language and Character Encoding Support Image Processing and Generation Mail Related Extensions Mathematical Extensions Non-Text MIME Output Process Control Extensions Other Basic Extensions Other Services Search Engine Extensions Server Specific Extensions Session Extensions Text Processing Variable and Type Related Extensions Web Services Windows Only Extensions XML Manipulation GUI Extensions Keyboard Shortcuts ? This help j Next menu item k Previous menu item g p Previous man page g n Next man page G Scroll to bottom g g Scroll to top g h Goto homepage g s Goto search

Php isset or