Frequency count of two column in R

Question

I have two columns in data frame

2010  1 2010  1 2010  2 2010  2 2010  3 2011  1 2011  2 

I want to count frequency of both columns and get the result in this format

  y    m Freq  2010  1 2  2010  2 2  2010  3 1  2011  1 1  2011  2 1  

Answer 1

I haven't seen a dplyr answer yet. The code is rather simple.

library(dplyr) rename(count(df, y, m), Freq = n) # Source: local data frame [5 x 3] # Groups: V1 [?] # #       y     m  Freq #   (int) (int) (int) # 1  2010     1     2 # 2  2010     2     2 # 3  2010     3     1 # 4  2011     1     1 # 5  2011     2     1 

Data:

df <- structure(list(y = c(2010L, 2010L, 2010L, 2010L, 2010L, 2011L,  2011L), m = c(1L, 1L, 2L, 2L, 3L, 1L, 2L)), .Names = c("y", "m" ), class = "data.frame", row.names = c(NA, -7L)) 

Answer 2

If your data is dataframe df with columns y and m

library(plyr) counts <- ddply(df, .(df$y, df$m), nrow) names(counts) <- c("y", "m", "Freq")