Redicrect Loop when trying to add www to htaccess - wordpress

Question

I was hoping someone could take a look at my htaccess setup and tell me if I'm doing something wrong. Every time I try to add in one of the numerous formats I've found to redirect my page to www, I get a redirect loop.
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
The above works, but it goes to the base page with no www.
I've tried the following setups, and none work.
RewriteEngine on
RewriteCond %{HTTP_HOST} !^www\.yoursite\.com
RewriteRule (.*) http://www.yoursite.com/$1 [R=301,L]
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteRule ^(.*)$ http://www.yoursite.com/$1 [R=301,L]
</IfModule>
RewriteEngine on
RewriteCond %{HTTP_HOST} !^www\.
RewriteRule ^(.*)$ http://www.%{HTTP_HOST}/$1 [R=301,L]

Answer 1

This is the code I add to the default .htaccess file that is setup with WordPress. To add the www I use:
RewriteEngine On
RewriteCond %{HTTP_HOST} ^your-site.com [NC]
RewriteRule ^(.*)$ http://www.your-site.com/$1 [L,R=301]
Make sure you update WordPress Address (URL) [under general settings] as well to include www.