Function printing but not working into an array - php

Question

We are having troubles trying to insert multiple values generated from a function into an array.
When we print the function using a string and we copy the results manually it works but when we try to make it work using the string into an array it doesn't.
<?php
function dateRange( $first, $last, $step = '+1 day', $format = 'm/d/Y' ) {
$current = strtotime( $first );
$last = strtotime( $last );
while( $current <= $last ) {
$dates .= "'" . date( $format, $current) . "', ";
$current = strtotime( $step, $current );
}
return $dates;
}
$all_dates = dateRange( '01/20/1999', '01/23/1999');
echo $all_dates; /* PRINTS ALL DATES BETWEEN TWO DATES: '01/20/1999', '01/21/1999', '01/22/1999', '01/23/1999', */
query_posts( array(
'post_type' => 'bbdd',
'meta_query' => array(
$location,
array(
'key' => 'date',
'value' => array($all_dates), /* DOESN'T WORK. INSTEAD, IF WE COPY THE RESULT OF "echo $all_dates;" MANUALLY, IT DOES WORK */
),
)
) );
?>

Answer 1

You're returning a string, not an array, in the function.
function dateRange( $first, $last, $step = '+1 day', $format = 'm/d/Y' ) {
$current = strtotime( $first );
$last = strtotime( $last );
while( $current <= $last ) {
$dates[] = date($format, $current);
$current = strtotime($step, $current );
}
return $dates;
}
That will return an array.
Then, in your mysql query:
'value' => $all_dates

Answer 2

Why not put it in an array in the first place:
<?php
function dateRange( $first, $last, $step = '+1 day', $format = 'm/d/Y' ) {
$dates = array();
$current = strtotime( $first );
$last = strtotime( $last );
while( $current <= $last ) {
$dates[] = date($format, $current);
$current = strtotime( $step, $current );
}
return $dates;
}
?>