API: expanding/rolling_std/var/cov and ddof · Issue #8064 · pandas-dev/pandas (original) (raw)

Though it's not mentioned in the doc strings, expanding/rolling_std/var support a ddof parameter, while expanding/rolling_cov do not (they effectively assume ddof=1).

I think it would be best if all these functions supported an explicit (i.e. documented) ddof parameter that defaults to 1.