问题
I've got a handle on MySQL and HTML, but am still learning PHP. I'm on a bit of a schedule, so when I noticed that Dreamweaver would write PHP for me I started using that feature. I immediately noticed that, of course, the code it inserts isn't that great.
When investigating "Notice: Undefined index:" I came across PHP error: Notice: Undefined index:.
DeaconDesperado pointed out that alibenmessaoud's code was trying to process before post values were set. So I looked into my code for the same problem and noticed that Dreamweaver is using
if ((isset($_POST["MM_insert"])) && ($_POST["MM_insert"] == "name_of_your_submit_input"))
instead of
if(isset($_POST) && array_key_exists('name_of_your_submit_input',$_POST))
Am I misunderstanding Dreamweaver's code? Isn't checking if the post is the submit name the same as checking if it exists? Am I misunderstanding array_key_exists()? Last question, does it matter that my check is above the form itself?
Thanks for putting up with a newbie who hasn't finished the w3schools PHP tutorial yet.
回答1:
The two examples you've given don't do the same thing, therefore neither is better.
Your first example is asking whether key MM_insert exists in $_POST and that it's value is name_of_your_submit_input.
Whereas your second example is asking whether the key name_of_your_submit_input exists, which could also look like this:
if (isset($_POST["name_of_your_submit_input"]))
In any case, both examples wouldn't cause that PHP Notice.
来源：https://stackoverflow.com/questions/16158800/is-array-key-existssubmit-input-name-post-better-than-postmm-insert