How to subset a contingency table in R?

Problem

We'd like to subset a contingency table. In our example, we use the dataset chickwts, subsetting those types of feed for which we have more than 11 observations.

table(chickwts$feed)

   casein horsebean   linseed  meatmeal   soybean sunflower 
       12        10        12        11        14        12

Solution

• Base package

Using the function subset.

subset(data.frame(table(chickwts$feed)), Freq > 11)

• dplyr

library(dplyr)
chickwts %>% 
  count(feed) %>%
  filter(n > 11) 

Results

 # base
      Var1 Freq
1    casein   12
3   linseed   12
5   soybean   14
6 sunflower   12

# dplyr

# A tibble: 4 × 2
       feed     n
      
1    casein    12
2   linseed    12
3   soybean    14
4 sunflower    12

References

• stackoverflow