CODEWITHSUNDEEP
rdplyr
Brandon Bertelsen
Brandon Bertelsen

Reputation: 44638

Spreading a list contained in a data.frame

A handy trick (especially for stat testing) is to convert a wide data.frame to a long data.frame with embedded lists.

df <- data.frame(
    A = sample(c(1:10),1000,replace = TRUE), 
    B = sample(c(1:10),1000,replace = TRUE), 
    C = sample(c(1:10),1000,replace = TRUE)) %>% 
    gather %>% group_by(key) %>% 
    summarize(response_list = list(value))

Given a data.frame with an embedded list, how do I append summary counts for each of the embedded lists so that the data.frame looks like this: 

key response_list 1 2 3 4 5 6 7 8 9 10
A   list()        x x x x x x x x x x 
...

where, x, is a respective count of the occurrence of each number in the embedded list (akin to table(factor(the_list()))

Upvotes: 0

Views: 56

Answers (1)

Pierre L
Pierre L

Reputation: 28441

df <- cbind(df, do.call(rbind, lapply(df$response_list, table)))
tbl_df(df)
# Source: local data frame [3 x 12]
#
#      key response_list     1     2     3     4     5     6     7     8     9    10
#   (fctr)         (chr) (int) (int) (int) (int) (int) (int) (int) (int) (int) (int)
# 1      A   <int[1000]>    97   105    97   100   103   103    86   101    90   118
# 2      B   <int[1000]>    98   100   108    92   115    87   101   105    98    96
# 3      C   <int[1000]>   109    97    87    92    91    90   114   109   104   107

Upvotes: 3

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