Comparing each values of each group to the minimum of the group

Question

I have data grouped by years. I would like to replace each data where x>(minimum+2) by NA. The minimum changes each year. I was thinking to extract the minimum by year using ddply, but i don't know how to compare each value from each year to their specific minimum...

Thanks a lot.

  New <-  Ancian %>%
group_by(Years) %>%
mutate_if(New$Data1, ~  replace(., . > (min(., na.rm = TRUE) + 2),  NA))

I tried this, but it doesn't work... Also tried to do a "if" function after a group_by, but no results too...

group_by(Years) %>%
if(New$Data1 > (min(New$Data, na.rm = TRUE) + 2)) { 
New$Data1 <- NA }

Answer 1

We can use mutate_if after doing a grouping by 'years'

library(dplyr)
df1update <-  df1 %>%
    group_by(years) %>%
    mutate_if(is.numeric, ~  replace(., . > (min(., na.rm = TRUE) + 2),  NA))

If we need to do this only for a single variable

df1update <- df1 %>%
               group_by(years) %>%
               mutate(Data1 = replace(Data1, Data1 > (min(Data1, na.rm = TRUE) + 2), NA))