[R] bootstrap help

[Casper]

Hi，

I have a dataframe with x and y in pairs, ( 49 pairs i.e. 49 rows )

x y
76 80
138 143
67 67
29 50
381 464
23 48
37 63
120 115
....

how do i generate 50 Bootstrap samples and corresponding estimates?

i have tried

sample( data, size=50,replace=T)

does not seem to be right

Thanks.