Reference Guide: What does this symbol mean in PHP? (PHP Syntax)

### What is this? This is a collection of questions that come up now and then about syntax in PHP. This is also a Community Wiki, so everyone is invited to participate in maintaining this list. **This question shouldn't be used as a dupe target for closing questions.** Use actual questions linked here as dupe targets instead. ### Why is this? It used to be hard to find questions about operators and other syntax tokens.¹ The main idea is to have links to existing questions on Stack Overflow, so it's easier for us to reference them, and not to copy over content from the PHP Manual. Note: Since January 2013, Stack Overflow [does support special characters][1]. Just surround the search terms by quotes, e.g. [`[php] "==" vs "==="`][2] ### **What should I do here?** If you have been pointed here by someone because you have asked such a question, please find the particular syntax below. The linked pages to the [PHP manual](http://php.net/manual/en/index.php) along with the linked questions will likely answer your question then. If so, you are encouraged to upvote the answer. This list is not meant as a substitute for the help others provide. ## The List If your particular token is not listed below, you might find it in the [List of Parser Tokens][3]. --- `&` [Bitwise Operators][4] or [References][5] - https://stackoverflow.com/questions/1676897 - https://stackoverflow.com/questions/600202 - https://stackoverflow.com/questions/2209934/ - https://stackoverflow.com/questions/2376348 - https://stackoverflow.com/questions/1006652 - https://stackoverflow.com/questions/2297592 - https://stackoverflow.com/questions/2422907 - https://stackoverflow.com/questions/2478149 - https://stackoverflow.com/questions/3957584 - https://stackoverflow.com/questions/4705262 - https://stackoverflow.com/questions/4705838 - https://stackoverflow.com/questions/21058439 (&$) --- `=&` [References][5] - https://stackoverflow.com/questions/1768343 - https://stackoverflow.com/questions/1367454 - https://stackoverflow.com/questions/3177342 - https://stackoverflow.com/questions/2081806 --- `&=` [Bitwise Operators][4] - https://stackoverflow.com/questions/1367454 - https://stackoverflow.com/questions/3177342 --- `&&` [Logical Operators][6] - https://stackoverflow.com/questions/2803321 - https://stackoverflow.com/questions/2376348 - https://stackoverflow.com/questions/4746865 - https://stackoverflow.com/questions/4502092 --- `%` [Arithmetic Operators][7] - https://stackoverflow.com/questions/1934173 - https://stackoverflow.com/questions/3204919 --- `!!` [Logical Operators][6] - https://stackoverflow.com/questions/2127260 --- `@` [Error Control Operators][8] - https://stackoverflow.com/questions/1032161 - https://stackoverflow.com/questions/3551527 - https://stackoverflow.com/questions/3984864...