Hide .php extention from urls with query string

Question

I am using .htaccess file for url rewriting . I've written all pages with .php extention and to hide them i am using this code

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^\.]+)$ $1.php [NC,L]`

But this hides when i write "www.example.com/abc.php" to "www.example.com/abc" . I want them to change automatically like when i click on a link

<a href="example.php">example</a>

then page link should open like "www.example.com/example" not "www.example.com/example.php"

Also how to hide "?var="hello" from all pages but variable should be sent to that page is that possible ?.

UPDATE

For example here i am using this

<?php 
if(isset($_GET['hi'])){
echo $_GET['hi'];
}
?>
<a href="a.php?hi=sdsdsd">a</a><br>
<a href="b.php">b</a><br>
<a href="c.php">c</a><br>
<a href="d.php">d</a><br>

I want what ever the page is should be accessed without extension and query string should be hided but must be accessed.

Answer 1

Use this .htaccess:

RewriteEngine On

# Unless directory, remove trailing slash
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^([^/]+)/$ http://example.com/folder/$1 [R=301,L]

# Redirect external .php requests to extensionless url
RewriteCond %{THE_REQUEST} ^(.+)\.php([#?][^\ ]*)?\ HTTP/
RewriteRule ^(.+)\.php$ http://example.com/folder/$1 [R=301,L]

# Resolve .php file for extensionless php urls
RewriteRule ^([^/.]+)$ $1.php [L]