CODEWITHSUNDEEP
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Natsy
Natsy

Reputation: 11

R how to create a column for each unique character in a column and populate with matching values

I have a dataframe like this:

Dataframe

I would like for it to be like this:

What I want

How do I do it? The length of the columns will be different for each column so I think it cant be a dataframe, maybe a list of lists?

Sorry for the pictures, I'm not savvy enough to put the code in here :(

Thanks in advance

Nat

Upvotes: 0

Views: 218

Answers (2)

arg0naut91
arg0naut91

Reputation: 14764

You could also do something like:

library(data.table)

df_new <- dcast(setDT(df), Column2 ~ Column1)[, lapply(.SD, na.omit)][!duplicated(A, B)][, Column2 := NULL]

This would give you a dataframe:

    A  B
1: 12  6
2: 23  8
3: 30 45

Upvotes: 1

arvi1000
arvi1000

Reputation: 9582

something like this would do the job:

# data
example_df <- data.frame(col1 = c('A', 'A', 'A', 'B','B','B'),
                         col2 = 1:6)


# split into list of data.frames by value of col1
# and apply a function to get unique values of col2
lapply(
  split(example_df, example_df$col1), 
  function(x) unique(x$col2)
  )

That will return a list like this:

$A
[1] 1 2 3

$B
[1] 4 5 6

Upvotes: 1

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