I would like to row bind two dataframes with different columns like bind_rows in R. I tried the same with vcat as in this question: Julia equivalent of dplyr's bind_cols and bind_rows, but I get an error. Here some reproducible code:

using DataFrames

df1 = DataFrame(a = 1, b = 1)
df2 = DataFrame(b = 1, c = 1)
vcat(df1, df2)

Output:

ArgumentError: column(s) c are missing from argument(s) 1, and column(s) a are missing from argument(s) 2

I don't know why this error happens, because in the answer of the question it does work. So I was wondering if anyone knows why this error happens and if this is the best way to bind two dataframes in Julia?

CodePudding user response：

The error occurs because those DataFrames have columns with different names (technically, properties). Use the cols=:union keyword argument:

vcat(df1, df2, cols=:union)
# 2×3 DataFrame
#  Row │ a        b      c
#      │ Int64?   Int64  Int64?
# ─────┼─────────────────────────
#    1 │       1      1  missing
#    2 │ missing      1        1

union holds a union of columns. cols have more options. check them out here if you are interested.