Question

I’m pretty sure I should be able to use arrayInd() to do this, but I’m still wrapping my head around R and I am missing something fundamental here.

I have a dataframe that includes two date columns. I calculated a new column with the difference between them. So now I have df$before_date, df$after_date and df$days_out.

I can do this to see the index for the maximum and minimum value in df$days_out:

> which.min(df$days_out)
[1] 18704
> which.max(df$days_out)
[1] 80183

And then I can go through and see the date info:

> df[80183, 5]
[1] "1973-12-17"
> df[80183, 6]
[1] "2010-08-13"
> df[80183, 12]
Time difference of 13388 days

I’m trying to figure out how to do that in one fell swoop, so I’d get a result like:

         df$before_date    df$after_date    df$days_out
[80183]  1973-12-17        2010-08-13       13388

What am I missing here?

Answer 1

Perhaps something like this?

df[80183, c(5,6,12)]

Or you can calculate the max and min values in one pass:

df[
  c(which.max(df$days_out),which.min(df$days_out)), 
  c('days_out','before_date','after_date')
  ]