(unless you touched the database) yes, your data is safe within the database when you delete the wordpres installation files (phew!). You should upload the version you were using, change your configuration file and it'll work. you may/may not have lost customized theme(s) and plugins but can re-upload those as well.
There's a great backup utility that I use that emails me a backup copy of my data on a daily basis. Before I delete any files off of my production/live server, I copy them all to my local machine in case I bugger something up which i myself have even done and I've been at this for over a decade now
i have always kept copies of each version of WP around in case I lose a site that has an older version of WP installed. same with my themes and plugins.
its always good to ensure your web hosting provides some sort of backups that can be restored. even they can lose data that can't be recovered which is why it's always a good idea to backup the data yourself in multiple areas if possible. redundancy is a good thing.