[R] Problem accessing "row number" from subset on a dataframe

[Mark Wardle]

Hi. I may be missing what you're trying to achieve, but...

what about

subset(airquality, airquality$Month!=6)

instead?

You can do arbitrarily complex queries if you wish, combining terms logically.

You don't have to use the subset function. You may find it helpful to
see what the following result in:

airquality$Month==6
airquality[airquality$Month==6, ]
airquality[airquality$Month==6, ]

There are ways of getting the row numbers, but I suspect you don't
actually need to do that, do you?

Best wishes,

Mark

2009/5/26 Jason Rupert <jasonkrupert at yahoo.com>:
>
>
> I would like to use the "row number" information returned from performing a subset command on a dataframe.
>
> For example, I would like to automatically delete some rows from a dataframe if they match a criteria.  Here is my example below.
>
> data(airquality)
> names(airquality)
> subset(airquality, airquality$Month == 6)
>
> Now how do I delete the row numbers returned automatically?
>
> I know I can type
> airquality_mod<-airquality[-c(32:60)]
>
> However, I would like to check the row information and then use it to delete the stuff out of the dataframe.
>
> Thank again for any feedback and insights.
>
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-- 
Dr. Mark Wardle
Specialist registrar, Neurology
Cardiff, UK