How to initialize empty dataframe of specified size

New to Julia
1

Hi my question is as stated in the title. So I want to know what is the easiest way to create a dataframe with the column names, the type of the column and the number of rows specified in the beginning. I know you can do the following:

using DataFrames

testDF = DataFrame(columnA = String[], columnB = Int64[], columnC = Float64[])
push!(testDF,["hi", 3, 78.9])

But this is very inefficient if you already know what the size of the dataframe is going to be.

So how could I also specify the size of the dataframe when initializing it?