CODEWITHSUNDEEP
rdplyrsubsetdata-manipulation
adkane
adkane

Reputation: 1441

How to conditionally delete group-specific factor levels in R

I have a data frame where I want to filter out the Month values if the count of its associated Index is < 2. 

ID = c(rep("A", 5), rep("B", 5))
Month = c(
  1,
  1,
  2,
  2,
  3,
  1,
  2,
  2,
  3,
  3
)
Index = c("X1", "X1", "X2", "X2", "X3", "X1", "X2", "X2", "X2", "X3")
df = data.frame(ID, Month, Index, stringsAsFactors =  FALSE)
df$Month <- as.factor(df$Month)
df

Here, X3 and X1 only occur once for A and B respectively so those rows would be deleted.

But if I try to filter my data using %in% for X3 and X1 they will also get removed from the other ID values.

The deletion should only be group specific.

Upvotes: 0

Views: 260

Answers (1)

akrun
akrun

Reputation: 887118

We can group by the columns and filter

library(dplyr)
df %>% 
  group_by(ID, Month, Index) %>%
  filter(n() >1)

Upvotes: 1

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