While messing with Python to output some better graphs for my Facebook group scraper I stumbled upon an interesting problem. What happens if you have missing samples, or want to change the sampling frequency half way through your log? Well, you could use a proper math library and have extra dependencies or generate the missing data manually, but the simplest answer I could think of was to write a list class which interpolates between missing values, so you can do something like this:

>>> a = InterpoList()
>>> a[0]   = 0
>>> a[100] = 200
>>> a[200] = 0
>>> a[50]
100.0
>>> a[125]
150.0

And then store the time values as seconds past the epoch. Now I can inject data from multiple sources taken at different frequencies and retrieve an interpolated value for any time, which means more nice graphs like this:

As usual I also decided to share it with the Internet, because I’m nice like that! You can get a copy of the InterpoList module here.