I’d like to create a violin plot of a `DataFrame`

and set each “violin” at its linear respective position. For example, this plot:

```
# some data to play with
n = 10000
f(k) = randn(k)
df2 = DataFrame(hcat(f(n).+1, f(n).-1, 2*f(n), 0.5*f(n)-3, 2*f(n).^2, abs.(f(n))),
map(num->Symbol(num),[4,10,15,20,22,30]));
# Now plot a violin of each "Set" on the same graph
@df df2 violin(cols(), xticks=(1:ncol(df2), names(df2)))
```

… has all the “violins” evenly spaced. I’d like to place them according to their numeric column name. I.e., the x-axis would be linear and the first “violin” would be centered above `4`

, the next would be centered above `10`

, …, and the last “violin” would be centered above `30`

.

How can this `violin`

plot be created?