Find all numbers in a certain interval

Hi all,

I'd like to know, if I can solve this with a shorter command:

a <- rnorm(100)
which(a > -0.5 & a < 0.5)

# would give me all indices of numbers greater than -0.5 and smaller than +0.5

I have something similar with a dataframe and it produces sometimes quite long 
commands...
I'd like to have something like:

which(within.interval(a, -0.5, 0.5))

Is there anything I could use for this purpose?


Antje