override filter in a plugin

Question

I am trying to remove two contactmethods that were set by a plugin. I've read a lot about adding/removing an action, but found little on adding/removing a filter.

Original plugin code:

function pg_contactmethods( $contactmethods ) {
$contactmethods[ 'twitter' ]  = 'Twitter';
$contactmethods[ 'facebook' ] = 'Facebook';

unset( $contactmethods[ 'aim' ] );
unset( $contactmethods[ 'yim' ] );
unset( $contactmethods[ 'jabber' ] );

return $contactmethods;
}
add_filter( 'user_contactmethods', 'pg_contactmethods', 10, 1 );

I can comment out the Twitter and Facebook lines and that works, but I don't want to modify the original plugin.

I have create a functionality plugin and added the following line:

remove_filter( 'user_contactmethods', 'pg_contactmethods', 10, 1 );

Nothing changed.

Tried using just these two lines in a new function:

unset ( $contactmethods[ 'twitter' ] );
unset ( $contactmethods[ 'facebook' ] );

Nothing changed.

Tried the following remove_filter/add_filter in my functionality plugin:

remove_filter ('user_contactmethods', 'pg_contactmethods', 10, 1);
add_filter ('user_contactmethods', 'my_contactmethods', 10, 1);
function my_contactmethods( $contactmethods ) {
//$contactmethods[ 'twitter' ]  = 'Twitter';
//$contactmethods[ 'facebook' ] = 'Facebook';

unset( $contactmethods[ 'aim' ] );
unset( $contactmethods[ 'yim' ] );
unset( $contactmethods[ 'jabber' ] );

return $contactmethods;
}

Again, nothing changed.

Any advice on what I'm doing wrong?

Edit: I'm using WP 4.3.1, with a child theme.

Answer 1

My mistake was that I was trying to remove the plugin's filter from within my own plugin. In order to modify a plugin's filter, the remove_filter() function must be in the child theme's functions.php file.