[R] [External Email] Group by and add a constant value based on a condition dply

[Rui Barradas]

Hello,

I too don't see why grouping is needed but here it goes.


df1 %>%
   group_by(Department, Class) %>%
   mutate(Value = Value + 5*(Date == "4.01.2020"))


Hope this helps,

Rui Barradas

Às 17:01 de 26/05/21, Christopher W Ryan via R-help escreveu:
> Is the grouping beforehand necessary? Could you simply, "for all the dates
> that are "4.01.2020"  and have the "Value" greater than zero  add 5 to the
> "Value" "?  I may be missing something.
> 
> --Chris Ryan
> 
> On Wed, May 26, 2021 at 11:53 AM Elahe chalabi via R-help <
> r-help using r-project.org> wrote:
> 
>> Hi everyone,
>>
>> I have the following dataframe:
>>
>>
>>
>>        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, 0L, 0L, 0L, 400L, 400L, 200L,
>>      800L, 1200L, 0L), Date = c("1.01.2020", "2.01.2020", "3.01.2020",
>>      "4.01.2020", "1.01.2020", "2.01.2020", "3.01.2020", "4.01.2020",
>>      "1.01.2020", "2.01.2020", "3.01.2020", "4.01.2020", "1.01.2020",
>>      "2.01.2020", "3.01.2020", "4.01.2020")), class = "data.frame",
>> row.names = c(NA,
>>       -16L))
>>
>>   using dplyr I need to group by "Depatment" and "Class" and then for all
>> the dates that are "4.01.2020"  and have the "Value" greater than zero  add
>> 5 to the "Value", meaning the desired dataframe will be (NewValue column) :
>>
>>
>>
>>     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, 0L, 0L, 0L, 400L, 400L, 200L,
>>   800L, 1200L, 0L), Date = c("1.01.2020", "2.01.2020", "3.01.2020",
>>   "4.01.2020", "1.01.2020", "2.01.2020", "3.01.2020", "4.01.2020",
>>   "1.01.2020", "2.01.2020", "3.01.2020", "4.01.2020", "1.01.2020",
>>   "2.01.2020", "3.01.2020", "4.01.2020"), NewValue = c(0L, 100L,
>>   800L, 805L, 0L, 300L, 1200L, 0L, 0L, 0L, 400L, 405L, 200L, 800L,
>>   1200L, 0L)), class = "data.frame", row.names = c(NA, -16L))
>>
>>
>> Thanks a lot for any help!
>> Elahe
>>
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> 
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> 
> ______________________________________________
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> and provide commented, minimal, self-contained, reproducible code.
>