Adding to a multidimensional array

I've tried searching for this but I just can't seem to get my head around it, hopefully someone can help.

This is the code I have:


$args = array(
'cat' => 5,
'meta_query' => array(
array(
'key' => '_mf_write_panel_id',
'compare' => '=',
'value' => 1
)
),
'meta_key' => 'number_of_bedrooms',
'orderby' => 'meta_value',
'order' => 'ASC'
);


and I want to turn the array into this:-


$args = array(
'cat' => 5,
'meta_query' => array(
array(
'key' => '_mf_write_panel_id',
'compare' => '=',
'value' => 1
),
array(
'key' => 'swimming_pool',
'compare' => '=',
'value' => 'yes');
),
'meta_key' => 'number_of_bedrooms',
'orderby' => 'meta_value',
'order' => 'ASC'
);


But... I need to add it in after the initial array has been created.

I've tried all sorts of variations of this:-

$args['meta-query'] = array('key' => 'swimming_pool','compare' => '=','value' => 'yes');

and array_push and anything else I can think of but it doesn't seem to be working.

It's to build a Wordpress query, so I need to use conditionals to decide whether to add the extra arrays into the query based on a search form on the preceding page.

Many thanks for any help offered.

<?php

$args = array(
'cat' => 5,
'meta_query' => array(
array(
'key' => '_mf_write_panel_id',
'compare' => '=',
'value' => 1
)
),
'meta_key' => 'number_of_bedrooms',
'orderby' => 'meta_value',
'order' => 'ASC'
);


array_push($args['meta_query'], array(
'key' => 'swimming_pool',
'compare' => '=',
'value' => 'yes'));

print_r($args);
?>

Perfect, thanks - could have sworn I tried something very similar to that but obviously not.

Thanks again.