CODEWITHSUNDEEP
r
desource90
desource90

Reputation: 3

Dataframe manipulation: Convert certain columns of a dataframe into a list based on a key value column

I have a DF like the example created by the code below.

a = data.frame( name = c(rep("Tim",5),rep("John",3)),id = c(rep(1,5),rep(2,3)), value = 1:7)

And I want to transform it into a result that looks like this.

b = data.frame( name = c("Tim","John"), ID = c(1:2), b = NA)
b$value = list(c(1:5),c(6:8))

How would I go about doing this transformation?

For the actual data frame, I will have many columns to the left of the ID column, which I will want to perform calculations on with the columns of lists that will be created on the right side of the ID field.

For example, on the DF b above, I might want to perform a function call with "Tim" as an argument and loop through each individual element in the list = {1,2,3,4,5} and the output of that loop is another list with the same number of elements.

Upvotes: 0

Views: 50

Answers (1)

akrun
akrun

Reputation: 886938

Try

aggregate(value~.,a, FUN=c)
# name id         value
#1  Tim  1 1, 2, 3, 4, 5
#2 John  2       6, 7, 8

data

a <- structure(list(name = structure(c(2L, 2L, 2L, 2L, 2L, 1L, 1L, 
1L), .Label = c("John", "Tim"), class = "factor"), id = c(1, 
1, 1, 1, 1, 2, 2, 2), value = 1:8), .Names = c("name", "id", 
"value"), row.names = c(NA, -8L), class = "data.frame")

Upvotes: 1

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