Convert daily pandas stock data to monthly data using first trade day of the month

Question

I have a set of calculated OHLCVA daily securities data in a pandas dataframe like this:

>>> type(data_dy)


        

Answer 1

I've seen in the last version of pandas you can use time offset alias 'BMS', which stands for "business month start frequency" or 'BM', which stands for "business month end frequency".

The code in the first case would look like

data_dy.resample('BMS', closed='right', label='right').apply(ohlc_dict)

or, in the second case,

data_dy.resample('BM', closed='right', label='right').apply(ohlc_dict)