[R] Keep ALL duplicate records

[jim holtman]

Here is a function I use to find all duplicate records

> allDup <- function (value)
{
    duplicated(value) | duplicated(value, fromLast = TRUE)
}
> x
     ID    OS  time
1 userA   Win 12:22
2 userB   OSX 23:22
3 userA   Win 04:44
4 userC Win64 12:28
> x[allDup(x$ID),]
     ID  OS  time
1 userA Win 12:22
3 userA Win 04:44
>



On Sun, Oct 2, 2011 at 2:18 PM, Pete Brecknock <Peter.Brecknock at bp.com> wrote:
>
> Erik Svensson wrote:
>>
>> Hello,
>> In a data frame I want to identify ALL duplicate IDs in the example to be
>> able to examine "OS" and "time".
>>
>> (df<-data.frame(ID=c("userA", "userB", "userA", "userC"),
>>   OS=c("Win","OSX","Win", "Win64"),
>>   time=c("12:22","23:22","04:44","12:28")))
>>
>>      ID    OS  time
>> 1 userA   Win 12:22
>> 2 userB   OSX 23:22
>> 3 userA   Win 04:44
>> 4 userC Win64 12:28
>>
>> My desired output is that ALL records with the same IDs are found:
>>
>> userA   Win 12:22
>> userA   Win 04:44
>>
>> preferably by returning logical values (TRUE FALSE TRUE FALSE)
>>
>> Is there a simple way to do that?
>>
>> [-- With duplicated(df$ID) the output will be
>> [1] FALSE FALSE  TRUE FALSE
>> i.e. not all user A records are found
>>
>> With unique(df$ID)
>> [1] userA userB userC
>> Levels: userA userB userC
>> i.e. one of each ID is found --]
>>
>> Erik Svensson
>>
>
>
> How about ...
>
> # All records
> ALL_RECORDS <- df[df$ID==df$ID[duplicated(df$ID)],]
> print(ALL_RECORDS)
>
> # Logical Records
> TRUE_FALSE <- df$ID==df$ID[duplicated(df$ID)]
> print(TRUE_FALSE)
>
> HTH
>
> Pete
>
>
> --
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>
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-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?