[R] Identifying duplicate rows?

[Rui Barradas]

Hello,

Please use dput(dfA) to post your data examples. The following is it's 
output. All one has to do is to copy and paste to an R session to get 
the data example.

dfA <-
structure(list(Site = c(929L, 929L, 930L, 930L, 931L, 932L),
State = structure(c(1L, 1L, 1L, 1L, 1L, 1L), .Label = "VA", class = 
"factor"),
Value = c(73L, 73L, 76L, 76L, 74L, 75L)), .Names = c("Site",
"State", "Value"), class = "data.frame", row.names = c(NA, -6L))

# Now use the argument 'fromLast'
dfA$dups <- duplicated(dfA) | duplicated(dfA, fromLast = TRUE)

Hope this helps,

Rui Barradas

Em 10-09-2012 19:23, kborgmann escreveu:
> Hi,
> I am trying to identify duplicate values in a column in a date frame.  The
> duplicated function identifies the duplicate rows in the data frame but it
> only does this for the second record, not both records. Is there a way to
> mark both rows in the data frame as TRUE?
> dfA$dups<-duplicated(dfA$Value)
> dfA
> Site	State Value dups
> 929	VA	73 FALSE
> 929	VA	73  TRUE
> 930	VA	76 FALSE
> 930	VA	76 TRUE
> 931	VA	74 FALSE
> 932	VA	75 FALSE
>
> But I would like this
> Site	State Value dups
> 929	VA	73 TRUE
> 929	VA	73  TRUE
> 930	VA	76 TRUE
> 930	VA	76 TRUE
> 931	VA	74 FALSE
> 932	VA	75 FALSE
>
> Thank you for your replies!
> Still on the learning curve,
> Kathi
>
>
>
> --
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