user7016618 user7016618 - 1 month ago 11
R Question

Concatenating all rows within a group using dplyr

Suppose I have a dataframe like this:

hand_id card_id card_name card_class
A 1 p alpha
A 2 q beta
A 3 r theta
B 2 q beta
B 3 r theta
B 4 s gamma
C 1 p alpha
C 2 q beta


I would like to concatenate the card_id, card_name, and card_class into one single row per hand level A, B, C. So the result would look something like this:

hand_id combo_1 combo_2 combo_3
A 1-2-3 p-q-r alpha-beta-theta
B 2-3-4 q-r-s beta-theta-gamma
....


I attempted to do this using group_by and mutate, but I can't seem to get it to work

data <- read_csv('data.csv')
byHand <- group_by(data, hand_id) %>%
mutate(combo_1 = paste(card_id),
combo_2 = paste(card_name),
combo_3 = paste(card_class))


Thank you for your help.

Answer

You were kind of close!

library(tidyr)
library(dplyr)

data <- read_csv('data.csv')
byHand <- group_by(data, hand_id) %>%
    summarise(combo_1 = paste(card_id, collapse = "-"), 
              combo_2 = paste(card_name, collapse = "-"),
              combo_3 = paste(card_class, collapse = "-"))

or using summarise_each:

 byHand <- group_by(data, hand_id) %>%
        summarise_each(funs(paste(., collapse = "-")))