shortcode to insert text depending on day of week - wordpress

Question

I would like to create a shortcode of [time] that would display 6:00-7:00AM everyday except for Saturday or Sunday, as those two days would display the time 8:00-9:00AM. How would I do this?
This is what I have come up with...
// [time]
function displaytime(){
if (date('l') == 'Saturday' || date('l') == 'Sunday')){
echo '8:00-9:00AM';
}else{ //it's a weekday
echo '6:00-7:00AM';
}
}
add_shortcode('time', 'displaytime');
// end display time
What it currently looks like... (next to Sat and Sun it should display 8:00-9;00AM)
I have 7 shortcodes to display the next 7 days of the week. So perhaps this is what is causing it to not work correctly?
// [tomorrow]
function displaydate_tomorrow(){
return date('D, M j.', strtotime('+1 day'));
}
add_shortcode('tomorrow', 'displaydate_tomorrow');
// end tomorrows date
// [tomorrow2]
function displaydate_tomorrow2(){
return date('D, M j.', strtotime('+2 day'));
}
add_shortcode('tomorrow2', 'displaydate_tomorrow2');
// end tomorrows date2
// [tomorrow3]
function displaydate_tomorrow3(){
return date('D, M j.', strtotime('+3 day'));
}
add_shortcode('tomorrow3', 'displaydate_tomorrow3');
// end tomorrows date3
// [tomorrow4]
function displaydate_tomorrow4(){
return date('D, M j.', strtotime('+4 day'));
}
add_shortcode('tomorrow4', 'displaydate_tomorrow4');
// end tomorrows date4
// [tomorrow5]
function displaydate_tomorrow5(){
return date('D, M j.', strtotime('+5 day'));
}
add_shortcode('tomorrow5', 'displaydate_tomorrow5');
// end tomorrows date5
// [tomorrow6]
function displaydate_tomorrow6(){
return date('D, M j.', strtotime('+6 day'));
}
add_shortcode('tomorrow6', 'displaydate_tomorrow6');
// end tomorrows date6
// [tomorrow7]
function displaydate_tomorrow7(){
return date('D, M j.', strtotime('+7 day'));
}
add_shortcode('tomorrow7', 'displaydate_tomorrow7');
// end tomorrows date7
// [time]
function displaytime(){
if (date('D') == 'Saturday' || date('D') == 'Sunday'){
return '8:00-9:00AM';
}else{ //it's a weekday
return '6:00-7:00AM';
}
}
add_shortcode('time', 'displaytime');
// end display time

Answer 1

It's stated in the docs:
Note that the function called by the shortcode should never produce output of any kind. Shortcode functions should return the text that is to be used to replace the shortcode.
try with this, and don't hesitate to comment if there is any issue:
// [time]
function displaytime(){
if (date('l') == 'Saturday' || date('l') == 'Sunday'){
return '8:00-9:00AM';
}else{ //it's a weekday
return '6:00-7:00AM';
}
}
add_shortcode('time', 'displaytime');
// end display time
EDIT after question update: The reason it displays the same time for all 7 places is because your initial code tests date('l') which only consider current day, so it will display '6:00-7:00AM' everywhere if current day is not Saturday or Sunday, or else '8:00-9:00AM' everywhere. In addition to this, you are creating 8 different shortcodes when only 1 should be enough for the 7 days, and the last for the time should be merged too, or else it has no way of knowing which day we consider.
EDIT 2: added code to set the wordpress timezone setting for the function, then restore to its original setting that was before the function.
updated code with a single shortcode for all (now you learn to add attributes to a shortcode!):
// use examples: [nextdaytime day="+1 day"] [nextdaytime day="+2 day"]
function displaynextdaytime($atts){
$originalZone = date_default_timezone_get(); //save timezone
date_default_timezone_set(get_option('timezone_string')); //set it to your admin value
$time = strtotime($atts['day']); //time for the date() function based on our 'day' attribute
if (date('l', $time) == 'Saturday' || date('l', $time) == 'Sunday'){
$timeStr = '8:00-9:00AM';
}else{ //it's a weekday
$timeStr = '6:00-7:00AM';
}
$returnVal = date('D, M j.', $time) . ' ' . $timeStr;
date_default_timezone_set($originalZone) //restore original zone
return $returnVal;
}
add_shortcode('nextdaytime', 'displaynextdaytime');
// end display next day and time