I have a Jailbroken iphone, need to erase all content ,but need to keep jailbroken.

if lets say, im about to meet with someone in few hours.
and i go to settings, reset, then delete all content and settings.
would this delete all info (such as, contacts,email,sms, calendars...) but still keep cydia in there? and maybe all the apps that are jailbroken?

awesome thanks.
but im a noob.
can you tell me more dirrectly how do i do it to get what i want?
i want nothing there at all.. no info nothing. except for the apps that come with phone and cydia.