Subtract the Column Wise Mean of a Large Matrix

As a service to export from a nice discussion (Not by me) in Slack.

I need to take a large matrix and subtract the mean columnwise and inplace. Is there a fast way to do this?
By columnwise I mean taking the mean of the column and subtracting it.

Answer by @Oscar_Smith:

for i in axes(A,2)
     @views A[:,i] .-= mean(A[:,i])

By @mcabbott

Or just A .-= mean(A, dims=1)

The loop is faster for large arrays.

Note that it is equivalent to A[:,i] .= A[:,i] .- mean(A[:,i]). Without @views, both of the slices on the right would allocate.