R round to nearest .5 or .1

Question

I have a data set of stock prices that have already been rounded to 2 decimal places (1234.56). I am now trying to round to a specific value which is different

Answer 1

Probably,

round(a/b)*b

will do the work.

> a <- seq(.1,1,.13)
> b <- c(.1,.1,.1,.2,.3,.3,.7)
> data.frame(a, b, out = round(a/b)*b)
     a   b out
1 0.10 0.1 0.1
2 0.23 0.1 0.2
3 0.36 0.1 0.4
4 0.49 0.2 0.4
5 0.62 0.3 0.6
6 0.75 0.3 0.6
7 0.88 0.7 0.7