[R] subsetting and NAs

[Patrick Drechsler]

Eric Archer wrote on 20 Mar 2006 19:46:44 MET:

> I'm getting some unexpected behavior with subsetting a data
> frame (aircraft flight data) that I can't sort out.  Here is a
> simplified version of my data frame and problem:
>
>  > flight
>       FlightID TailNo FlightDate HobbsTime FlightCost       Date year
> 1         4497  6009K       <NA>       2.2      330.0       <NA>   NA
> 2         4498  6009K       <NA>       0.8      120.0       <NA>   NA
> 3         4499  6009K       <NA>       0.9      135.0       <NA>   NA
> 4         4500  6009K       <NA>       1.1      165.0       <NA>   NA
> 5         4501  6009K       <NA>       1.5      225.0       <NA>   NA
> 2587      7083  9206N   4/8/2009       1.5      103.5 2009-04-08 2009
> 2588      7084  9206N  4/10/2009       1.3       89.7 2009-04-10 2009
> 2589      7085  9206N  4/11/2009       1.9      131.1 2009-04-11 2009
> 2590      7086  9206N  4/12/2009       1.3       89.7 2009-04-12 2009
> 2591      7087  9206N  4/15/2009       1.1       75.9 2009-04-15 2009
> 29793    35208  91630  1/21/2006       1.4      107.8 2006-01-21 2006
> 29794    35209  91630  1/21/2006       0.7       53.9 2006-01-21 2006
> 29795    35210  9725B  1/21/2006       1.4      138.6 2006-01-21 2006
> 29796    35212  91630  1/28/2006       1.0       77.0 2006-01-28 2006
> 29797    35213  91630  1/28/2006       1.6      123.2 2006-01-28 2006
> 29798    35214  3386E   1/5/2006       1.1       86.9 2006-01-05 2006
>
> I then try to extract the error years :

flight <- flight[complete.cases(flight),]# <- delete rows with NaNs

> errors <- flight[flight$year > 2006,]
> errors

     FlightID TailNo FlightDate HobbsTime FlightCost                Date year
2587     7083  9206N   4/8/2009       1.5      103.5 2009-04-08 08:00:00 2009
2588     7084  9206N  4/10/2009       1.3       89.7 2009-04-10 08:00:00 2009
2589     7085  9206N  4/11/2009       1.9      131.1 2009-04-11 08:00:00 2009
2590     7086  9206N  4/12/2009       1.3       89.7 2009-04-12 08:00:00 2009
2591     7087  9206N  4/15/2009       1.1       75.9 2009-04-15 08:00:00 2009


HTH

Patrick
-- 
Geld ist besser als Armut - wenn auch nur aus finanziellen Gründen.
                                                      [Woody Allen]