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rdatabasedataframeaggregate

Select top 10 lowest values by group

I'm trying to get the top 10 lowest 'key_val' for each group = 'loc'

Table df2:

Trends loc key_val
trend1 Nigeria 1
trend1 Nigeria 1
trend2 Nigeria 2
trend2 Nigeria 2
trend3 France 3
trend4 France 4
trend5 France 5
trend6 France 6
trend6 France 6

The table is not exhaustive but an example

I tried the following code:

data_new3 <- df2[order(df2$key_val, decreasing = FALSE), ]  
data_new3 <- data.table(data_new3, key = "loc")
data_new3 <- data_new3[ , tail(.SD, 10), by = loc]
data_new3

The result does not take into account the top 10 lowest values (key_val), but only the first or second.... I don't know how to solve this problem, can anyone help me?

Solution

  • We may do

    library(dplyr)# version >= 1.1.0
df1 %>%
   slice_min(key_val, n = 10, by = loc)