为什么在数组中单引号根据语法不需要

Question

I have some little confusion. I want to access the array as follows.

$_POST['un'];

or

  $arr['empno'];

But when I try in double quotes, it gives out a compile time error I tried the following:

 echo "welcome $_POST['un']";

in un i saved username by query string which is out of this question i think.. .so i write welcome i also tried

    echo "$array['emp']";

it also gives me an error. Whats the problem?

Answer 1

Further adding to Fred's comment, if you would like to use array variable, you can use it like:

echo "welcome $_POST[un]";

This will output the value of array variable