strsplit question

Dear R People:

I have the following set of data

Block[1:5]

[1] "5600-5699" "6100-6199" "9700-9799" "9400-9499" "8300-8399"

and I want to split at the -

strsplit(Block[1:5],"-")

[[1]]
[1] "5600" "5699"

[[2]]
[1] "6100" "6199"

[[3]]
[1] "9700" "9799"

[[4]]
[1] "9400" "9499"

[[5]]
[1] "8300" "8399"

What is the best way to extract the pieces that are to the left of the
dash, please?

Thanks,
Erin

Erin Hodgess
Associate Professor
Department of Computer and Mathematical Sciences
University of Houston - Downtown
mailto: erinm.hodgess at gmail.com