# [R] Group by and duplicate a value/dplyr

Gerrit Eichner gerr|t@e|chner @end|ng |rom m@th@un|-g|e@@en@de
Tue May 11 13:26:10 CEST 2021

```Homework?

Try maybe

mutate(MinValue = min(Value[Value != 0]) )

or

mutate(MinValue = sort(unique(Value))[2])

Hth  --  Gerrit

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Am 11.05.2021 um 13:11 schrieb Elahe chalabi via R-help:
> Hi all,
>
> I have the following data frame
>
>
> dput(df)
>      structure(list(Department = c("A", "A", "A", "A", "A", "A", "A",
> "A", "B", "B", "B", "B", "B", "B", "B", "B"), Class = c(1L, 1L,
> 1L, 1L, 2L, 2L, 2L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L), Value = c(0L,
> 100L, 800L, 800L, 0L, 300L, 1200L, 1200L, 0L, 0L, 400L, 400L,
> 200L, 800L, 1200L, 1200L)), class = "data.frame", row.names = c(NA,
> -16L))
>
>
> I would like to group by "Department" and "Class" and repeat the minimum value of "Valule" excluding zeros or get the second minimum value. The desired output is:
>
>
>      dput(df)
>      structure(list(Department = c("A", "A", "A", "A", "A", "A", "A",
> "A", "B", "B", "B", "B", "B", "B", "B", "B"), Class = c(1L, 1L,
> 1L, 1L, 2L, 2L, 2L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L), Value = c(0L,
> 100L, 800L, 800L, 0L, 300L, 1200L, 1200L, 0L, 0L, 400L, 400L,
> 200L, 800L, 1200L, 1200L), MinValue = c(100L, 100L, 100L, 100L,
> 300L, 300L, 300L, 300L, 400L, 400L, 400L, 400L, 200L, 200L, 200L,
> 200L)), class = "data.frame", row.names = c(NA, -16L))
>
>
> how should I change the following dplyr to give me the desired output?
>
>
>     df <-
>    df %>%
>    group_by(Department,Class) %>%
>    mutate(MinValue=min(Value) )
>
>
> Thanks for any help.
> Elahe
>
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```