CODEWITHSUNDEEP
rdplyrtidyverse
skurp
skurp

Reputation: 399

Coerce dataframe groups to list

I have a dataframe such as 

id <- c(1,1,1,2,2,3,3,3,3)
element <- c(25122,356,4454,5432,342340,12443,12354,123536,234134)
df <- data.frame(id = as.factor(id), element)

I would like to create a list of the id groups with their corresponding elements such as:

dflist <- list(c(25122,356,4454), c(5432,342340), c(12443,12354,123536,234134))

Upvotes: 3

Views: 57

Answers (2)

moodymudskipper
moodymudskipper

Reputation: 47300

Here's a solution with tapply:

library(magrittr)
df %$% tapply(element,id,list)

(elements are named with id, add %>% unname if it's an issue)

Upvotes: 1

akrun
akrun

Reputation: 887048

We can use split

unname(split(df$element, df$id))

Or with unstack

unname(unstack(df, element ~id))

Upvotes: 4

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