Thursday, May 24, 2012

Reference - What does this symbol mean in PHP?


What is this?



This is a collection of questions that come up every now and then about syntax in PHP. This is also a Community Wiki, so everyone is invited to participate in maintaining this list.



Why is this?



Stack Overflow does not allow searching for particular characters. As a consequence, many questions about operators and other syntax tokens are not found easily when searching for them. This also makes closing duplicates more difficult. The list below is to help with this issue.



The main idea is to have links to existing questions on Stack Overflow, so it's easier for us to reference them, not to copy over content from the PHP Manual.



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 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 to the help others provided.



The List



If your particular token is not listed below, you might find it in the List of Parser Tokens .




& Bitwise Operators or References





=& References





&= Bitwise Operators





&& Logical Operators





% Arithmetic Operators





!! Logical Operators





@ Error Control Operators





?: Ternary Operator





: Alternative syntax for control structures , Ternary Operator





:: Scope Resolution Operator , Namespaces





-> Classes And Objects





=> Arrays





^ Bitwise Operators





>> Bitwise Operators





<< Bitwise Operators





<<< Heredoc or Nowdoc





= Assignment Operators





== Comparison Operators





=== Comparison Operators





!== Comparison Operators





!= Comparison Operators





<> Comparison Operators





| Bitwise Operators





|| Logical Operators





~ Bitwise Operators





+ Arithmetic Operators , Array Operators





+= Assignment Operators





++ Incrementing/Decrementing Operators





.= Assignment Operators





. String Operators





, Function Arguments





$$ Variable Variables





` Execution Operator





<?= Short Open Tags





[] Arrays




Source: Tips4all
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1 comment:

  1. UserMay 24, 2012 at 3:43 AM

    Incrementing / Decrementing Operators

    ++ increment operator

    -- decrement operator

    Example Name Effect
    ---------------------------------------------------------------------
    ++$a Pre-increment Increments $a by one, then returns $a.
    $a++ Post-increment Returns $a, then increments $a by one.
    --$a Pre-decrement Decrements $a by one, then returns $a.
    $a-- Post-decrement Returns $a, then decrements $a by one.


    These can go before or after the variable. Putting this operator before the variable is slightly faster.

    If put before the variable, the increment / decrement operation is done to the variable first then the result is returned. If put after the variable, the variable is first returned, then the increment / decrement operation is done.

    For example:

    $apples = 10;
    for ($i = 0; $i < 10; ++$i)
    {
    echo 'I have ' . $apples-- . " apples. I just ate one.\n";
    }


    Live example

    In the case above ++$i is used, since it is faster. $i++ would have the same results.

    However, you must use $apples--, since first you want to display the current number of apples, and then you want to subtract one from it.

    You can also increment letters in PHP:

    $i = "a";
    while ($i < "c")
    {
    echo $i++;
    }


    Once z is reached aa is next, and so on.


    Note that character variables can be incremented but not decremented and even so only plain ASCII characters (a-z and A-Z) are supported.




    Stack Overflow Posts:


    Understanding Incrementing

    ReplyDelete

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