Strange behaviour of as.integer()

I would like to thank all those who wrote helpful and interesting
replies to my question. I could have saved myself the time for writing
it up had I simply read ?as.integer. However, under the circumstances in
which I first encountered as.integer's truncating behaviour this was not
so obvious because as.integer was called implicitly. To summarize my
initial problem:

length(rep(0, .57 * 100))

[1] 56