Nash
#1
I have two DataFrames. One contains simply one column. The other contains multiple columns. The DataFrames have the same number of rows.

How do I subtract the values in the first DataFrame from the corresponding values in all columns of the second DataFrame?

Best to just use a `for`

loop

```
julia> df1 = DataFrame(a = fill(100, 10));
julia> df2 = DataFrame(rand(10, 10), :auto);
julia> for n in names(df2)
df2[:, n] .= df2[:, n] .- df1.a
end
```

You can also use broadcasting, `df2 .- df1[:, "a"]`

4 Likes

or just `df2 .-= df1.a`

for an in-place operation.

5 Likes