Removing non-trading minutes in a trading day?

[mingzhou]

Hi, if I want to plot financial data in minute-scale, can I remove non-trading minutes to get a continuous axis scale? Thank you!

[dvmlls]

Hey!

Currently bdscale only does a business date scale...hence the name. You're asking for a business time scale, which is the same concept but with a couple additional restrictions.

So the short answer is no, it can't.

In order to get it to work though, you'd just need to implement two functions:

1. transform: given an actual time t in some time format like POSIXct, return an integer or double bt representing how long t occurred after some point in time epoch on your business-time scale
2. inverse: given a bt, how do I get a t

For transform you'd need to know:

• business.dates like you do for bdscale to account for weekends and holidays
• when the market opens and closes
• half trading days
• additional rules like if you're in Japan and the market closes in the middle of the day, etc

That would make it work. To make it pretty, you'd also need to implement a function that determines where to put the grid lines.