I have recently started to work on some statistical problems in R and I have a query. I normally code in python and find the "collections.Counter" function quite useful. However I did not find any such equivalent command in R which was surprising since frequencies are used a lot in statistics.
for e.g. I have this table (data frame) -
df ->
c1 c2
reading1 2
reading2 3
reading3 1
reading4 3
reading5 2
reading6 4
reading7 1
reading8 2
reading9 4
reading10 5
and I want to get this in R-
value frequency
1 2
2 3
3 2
4 2
5 1
I hope this illustrates what I would like to do.. Any help is appreciated
and for illustration purposes - In python I could do this -
df_c2 = [2,3,1,3,2,4,1,2,4,5]
counter=collections.Counter(df$c2)
print (counter)
and get this - Counter({2: 3, 1: 2, 3: 2, 4: 2, 5: 1})
which I can manipulate using loops.
The simplest way is to use table(), which returns a named vector():
> table(df$c2)
1 2 3 4 5
2 3 2 2 1
You can return a data.frame like this:
> data.frame(table(df$c2))
Var1 Freq
1 1 2
2 2 3
3 3 2
4 4 2
5 5 1
You can, of course, also use packages like the "tidyverse".
library(tidyverse)
df %>%
select(c2) %>%
group_by(c2) %>%
summarise(freq = n())
# # A tibble: 5 x 2
# c2 freq
# <int> <int>
# 1 1 2
# 2 2 3
# 3 3 2
# 4 4 2
# 5 5 1