dot(.) not supported as array keys character after form submit

Question

I have an array like:

$arr = array("a.b" => "a.b", "b.c" => "b.c");

When i print this it simply displays

Array ( [a.b] => a.b [b.c] => b.c )

But when i use a loop to use the key and value in checkbox name and values like:

<form action="" method="post">
    <ul>
    <?php
    foreach($arr as $k => $v){?>
        <li><input type="checkbox" name="<?php echo $v;?>" value="<?php echo $k;?>"><?php echo $v;?></li>
    <?php }?>
    </ul>
    <input name="sub" type="submit"/>
</form>

When i press the submit button the result shows like:

Array ( [a_b] => a.b [b_c] => b.c [sub] => Submit )

Look at the output array, the keys are changed, The dot(.) replaces with _.

Why this happen??

Possible duplicate of [Why strings in $\_POST can not contain a dot "."?](http://stackoverflow.com/questions/3742653/why-strings-in-post-can-not-contain-a-dot) — billyonecan, Jun 06 '16 at 08:05
This probably duplicate of http://stackoverflow.com/questions/68651/get-php-to-stop-replacing-characters-in-get-or-post-arrays — Oli, Jun 06 '16 at 08:12
You mean just for `register_global` the index changed the dot with underscore?? — , Jun 06 '16 at 08:12

score 1 · Answer 1 · answered Jun 06 '16 at 08:16

Please look at variables.external documentation

Dots and spaces in variable names are converted to underscores. For example <input name="a.b" /> becomes $_REQUEST["a_b"].

You can overcome this by using file_get_contents('php://input'); and then reading and parsing the input on your own if you cannot avoid dots in the variable names that come through GET or POST.

dot(.) not supported as array keys character after form submit

1 Answers1