Try also
subset(x, as.Date(Inspected, "%m/%d/%y") > as.Date(Sold, "%m/%d/%y") )
HTH,
Jorge.-
On Mon, Dec 26, 2011 at 9:32 PM, Jorge I Velez <> wrote:
> Hi Eric,
>
> Try
>
> # data
> x <- structure(list(House_number = 1:4, Inspected = structure(c(3L,
> 4L, 1L, 2L), .Label = c("10/31/2011", "8/3/2011", "9/2/2011",
> "9/4/2011"), class = "factor"), Sold = structure(c(1L, 2L, 4L,
> 3L), .Label = c("10/10/2011", "10/20/2011", "11/1/2011", "8/28/2011"
> ), class = "factor")), .Names = c("House_number", "Inspected",
> "Sold"), class = "data.frame", row.names = c(NA, -4L))
>
> > with(x, as.Date(Inspected, "%m/%d/%y") - as.Date(Sold, "%m/%d/%y") > 0)
> [1] FALSE FALSE TRUE FALSE
>
> > x[with(x, as.Date(Inspected, "%m/%d/%y") - as.Date(Sold, "%m/%d/%y") >
> 0), ]
> House_number Inspected Sold
> 3 3 10/31/2011 8/28/2011
>
> See ?as.Date for more information.
>
> HTH,
> Jorge.-
>
>
>
> On Mon, Dec 26, 2011 at 7:52 PM, Eric Wolff <> wrote:
>
>> Hi,
>>
>> I hope this isn't a really simple question, I've been struggling with it
>> for a while.
>>
>> I'm looking for a way to get a function to go through a data frame line by
>> line, compare fields, and produce a result, kind of a transform and an if
>> statement combined (I tried to put them together and it didn't work).
>>
>> So, consider data Sales:
>>
>> House number Inspected Sold
>> 1 9/2/2011 10/10/2011
>> 2 9/4/2011 10/20/2011
>> 3 10/31/2011 8/28/2011
>> 4 8/3/2011 11/1/2011
>>
>> I want to find all the records which were inspected after they were sold.
>> Ideally, this code would create a fourth field that would be a logical.
>>
>> I tried
>>
>> Sales<-transform(Sales, Checked=if(Sales$Inspected <= Sales$Sold) "OK")
>>
>> But that busted. I've bent over backward to make these kinds of
>> comparisons
>> work, but there has to be a better way. Any help would be most welcome.
>>
>> Thanks,
>>
>> Eric
>>
>> [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>
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