Asymmetric error bars are not supported for series (only dataframes) · Issue #9536 · pandas-dev/pandas (original) (raw)

According to the documentation, asymmetric error bars should be able to be passed in to plot as an Mx2 array for a Series object or a Mx2xN array for a DataFrame object.

However, the code only seems to parse this correctly for a DataFrame: https://github.com/pydata/pandas/blob/master/pandas/tools/plotting.py#L1338

When passing raw error values as yerr, it seems that the first values are used as two-sided error differences, instead of being plotted as raw upper and lower values. Note the symmetric error bars below:

Using the underlying matplotlib function directly yields the expected results, but without the pandas-generated decorations:

This was originally noted in this StackOverflow question and I corroborated the other user's experience.