Find all numbers in a certain interval
Antje wrote:
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?
Not in general, but in this particular case "abs(a) < 0.5" gives you the right result. By the way, some advice I read many years ago (in Kernighan and Plauger): always use < or <=, avoid > or >= in multiple comparisons. It's easier to read -0.5 < a & a < 0.5 than it is to read the form you used, because it is so much like the math notation -0.5 < a < 0.5. Duncan Murdoch