Converting a list to a data frame

Hello,

No, it's not possible to work with a matrix in ggplot2.
Not even with an object of class "list".

l <- list(x=1:5, y=1:5)
d <- as.data.frame(l)
m <- as.matrix(d)

library(ggplot2)
ggplot(l, aes(x, y)) + geom_point()  # Error
ggplot(d, aes(x, y)) + geom_point()  # OK, as expected
ggplot(m, aes(x, y)) + geom_point()  # Error

Hope this helps,

Rui Barradas


?s 22:31 de 24/07/21, Jeff Reichman escreveu:

Duncan

I need to plot the results (ggplot2) and I'm thinking I can only use a data.frame object in ggplot2. It is a rath r large "list" over 1 million rows. It is possible to work with a matrix in ggplot2?

Jeff

-----Original Message-----
From: Duncan Murdoch <murdoch.duncan at gmail.com>
Sent: Saturday, July 24, 2021 12:03 PM
To: reichmanj at sbcglobal.net; R-help at r-project.org
Subject: Re: [R] Converting a list to a data frame

Others have shown you how to extract the matrix and convert it to a dataframe.  My only addition is to suggest that you don't do this:
matrix methods are often much more efficient than dataframe methods, so if you can work with the matrix without conversion, you'll often find things run a lot faster.

Duncan Murdoch

On 24/07/2021 9:18 a.m., Jeff Reichman wrote:

How does one convert a list into a data frame?

    

str(weight_chains)

List of 1

$ : 'mcmc' num [1:100000, 1:3] -105 -105 -105 -104 -103 ...

     ..- attr(*, "dimnames")=List of 2

     .. ..$ : NULL

     .. ..$ : chr [1:3] "a" "b" "s"

     ..- attr(*, "mcpar")= num [1:3] 1001 101000 1

- attr(*, "class")= chr "mcmc.list"

    

Such that ..

    

weight_chains



                  a         b         s

1     -104.72512 1.0141407  9.369227

2     -104.52297 1.0167432  9.131354

3     -104.72669 1.0139528  9.219877

    


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