http://systemelemaitre.com/?smerdit=site-de-rencontre-moins-cher&8de=da R commands examining data and its structures
ls() or objects() # list variables
structure()
str() # summary of data
levels()
dim() # dimension of data
class() # show the class of the variable
head() or tail() # showing parts of data

http://boisdebout53.org/?syleyman1=sites-de-rencontres-portugais-gratuit&1d0=e0 http://www.statmethods.net/input/contents.html