Matrix

> library('datasets')
> WorldPhones
	 N.Amer Europe Asia S.Amer Oceania Africa Mid.Amer
1951  45939  21574 2876   1815    1646     89      555
1956  60423  29990 4708   2568    2366   1411      733
1957  64721  32510 5230   2695    2526   1546      773
1958  68484  35218 6662   2845    2691   1663      836
1959  71799  37598 6856   3000    2868   1769      911
1960  76036  40341 8220   3145    3054   1905     1008
1961  79831  43173 9053   3338    3224   2005     1076
> class(WorldPhones)
[1] "matrix"
> WorldPhones[1]
[1] 45939
> WorldPhones[1,1]
[1] 45939
> WorldPhones[1,2]
[1] 21574
> WorldPhones[1,]
  N.Amer   Europe     Asia   S.Amer  Oceania   Africa Mid.Amer 
   45939    21574     2876     1815     1646       89      555 
> WorldPhones[,1]
 1951  1956  1957  1958  1959  1960  1961 
45939 60423 64721 68484 71799 76036 79831 
> as.numeric(WorldPhones[,1])
[1] 45939 60423 64721 68484 71799 76036 79831