rbind dataframes with a different column name

Question

I\'ve 12 data frames, each one contains 6 columns: 5 have the same name, 1 is different. Then when I call rbind() I get:

Error in match.names(cla         


        

Answer 1

Another base R approach if you have data.frames with different column names:

# Create a list of data frames
df_list <- list()
df_list[[1]] <- data.frame(x = 1, y = paste0("y1", 1:3))
df_list[[2]] <- data.frame(x = 2, y = paste0("y2", 1:4))
df_list[[3]] <- data.frame(x = 3, y = paste0("y3", 1:5), z = "z3")
df_list
#> [[1]]
#>   x   y
#> 1 1 y11
#> 2 1 y12
#> 3 1 y13
#> 
#> [[2]]
#>   x   y
#> 1 2 y21
#> 2 2 y22
#> 3 2 y23
#> 4 2 y24
#> 
#> [[3]]
#>   x   y  z
#> 1 3 y31 z3
#> 2 3 y32 z3
#> 3 3 y33 z3
#> 4 3 y34 z3
#> 5 3 y35 z3

# This works when the column names are the same
do.call(rbind, df_list[1:2])
#>   x   y
#> 1 1 y11
#> 2 1 y12
#> 3 1 y13
#> 4 2 y21
#> 5 2 y22
#> 6 2 y23
#> 7 2 y24

# but fails when the column names differ
do.call(rbind, df_list)
#> Error in rbind(deparse.level, ...): numbers of columns of arguments do not match

# This can fill the unmatched columns with NA's without 
# depending on other packages:
Reduce(rbind, Map(function(x) {
  x[, setdiff(unique(unlist(lapply(df_list, colnames))), names(x))] <- NA; 
  return(x)
  }, 
  df_list))
#>    x   y    z
#> 1  1 y11 
#> 2  1 y12 
#> 3  1 y13 
#> 4  2 y21 
#> 5  2 y22 
#> 6  2 y23 
#> 7  2 y24 
#> 8  3 y31   z3
#> 9  3 y32   z3
#> 10 3 y33   z3
#> 11 3 y34   z3
#> 12 3 y35   z3