Join dataframes, retaining column names

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I have the following 3 data frames, each of which has columns with names. I want to combine them and retain the column names. When I use the patch I found for combining dataframes, it drops that name on any dataframes that don't have at least 2 columns. How can I retain the names?

x<-data.frame(mean(1:10))
names(x)[names(x) == 'mean.1.10.'] <- 'var.name'
y<-data.frame(1:4)
names(y)[names(y) == 'X1.4'] <- 'var.name2'
z<-data.frame(matrix(1:10,5,2))
names(z)[names(z) == 'X1'] <- 'var.name3'
names(z)[names(z) == 'X2'] <- 'var.name4'

list_datf <- list(x, y, z)
n_r <- seq_len(max(sapply(list_datf, nrow)))
NEW <- do.call(cbind, lapply(list_datf, `[`, n_r, ))
dataframe r merge
1 Answers

You need to include drop = FALSE in the indexing step so that the things you're binding together retain all of their dimensions. I couldn't figure out a way to do this by passing drop = FALSE as an extra argument to [, so I resorted to using an anonymous function instead.

NEW <- do.call(cbind, lapply(list_datf, function(x) x[n_r, , drop = FALSE]))

Alternatively, you could convert your components to tibbles, which (unlike data frames) never drop "unneeded" dimensions:

NEW <- do.call(cbind, lapply(list_datf, function(x) tibble::as_tibble(x)[n_r, ]))

If you want to go full tidyverse:

library(dplyr)
list_datf %>% purrr::map(~ tibble::as_tibble(.)[n_r, ]) %>% bind_cols()
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