How to replace the values in a binary matrix with values from a dataframe?

Question

The matrix I have looks something like this:

Plot   A  B  C  

 1     1  0  0

 2     1  0  1

 3     1  1  0

And I have a dataframe that looks like this

A  5
B  4
C  2

What I would like to do is replace the "1" values in the matrix with the corresponding values in the dataframe, like this:

Plot   A  B  C  

 1     5  0  0

 2     5  0  2

 3     5  4  0

Any suggestions on how to do this in R? Thank you!

akrun · Accepted Answer · 2022-10-17 20:15:50Z

1

An option with tidyverse

library(dplyr)
df1 %>%
    mutate(across(all_of(df2$col1),
    ~ replace(.x, .x== 1, df2$col2[match(cur_column(), df2$col1)])))

-output

 Plot A B C
1    1 5 0 0
2    2 5 0 2
3    3 5 4 0

data

df1 <- structure(list(Plot = 1:3, A = c(1L, 1L, 1L), B = c(0L, 0L, 1L
), C = c(0L, 1L, 0L)), class = "data.frame", row.names = c(NA, 
-3L))

df2 <- structure(list(col1 = c("A", "B", "C"), col2 = c(5, 4, 2)), 
class = "data.frame", row.names = c(NA, 
-3L))

answered Oct 17, 2022 at 20:15

akrun

891k38 gold badges590 silver badges700 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

hmich77 Over a year ago

Thank you, that seems like it should work. However, I get an error that the columns "don't exist" even though they certainly do in both dataframes. Is the issue that they need to be in the same order and of the same length? Because currently they are not. Error is " ! Can't subset columns that don't exist."

akrun Over a year ago

@hmich77 If you check the df2 with col1 in my post, it gives the same values you showed. Your example didn't show the column names, so i used col1, col2

Collectives™ on Stack Overflow

How to replace the values in a binary matrix with values from a dataframe?

1 Answer 1

data

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

data

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related