[R] middle of interval

[Duncan Murdoch]

On 08/02/2016 5:09 AM, catalin roibu wrote:
> Dear R users!
>
> I have a data frame with first column is an interval (1902-1931) and I want
> to find the middle of the interval? Is there a possibility to do that in R?
>
> Thank you very much!
>
> Best regards!
>

I don't know of a single function that does that, but the way to do it 
would be to separate the interval into two numbers, then take the 
average.  If your intervals are strings in the form shown above (not 
including the parentheses), this would work:

interval <- "1902-1931"
start <- as.numeric(sub("-.*", "", interval))
stop  <- as.numeric(sub(".*-", "", interval))
(start + stop)/2

Duncan Murdoch