Selecting data from data range.

Pulling data that meets specific conditions is one of the most powerful and commonly used operations with DataFrames. You can try it now with Alphabet stock data. Provided is the DataFrame alphabet and the datetimes start_date and end_date. The DataFrame's head looks like this:

date	close	volume	open	high	low
2019-08-02	1196.32	1745450	1203.00	1209.500	1190.00
2019-08-01	1211.78	1771271	1217.63	1236.298	1207.00
2019-07-31	1218.20	1997999	1224.87	1234.910	1208.18
2019-07-30	1228.00	1430775	1227.00	1236.910	1225.32
2019-07-29	1241.84	2069127	1242.50	1248.995	1230.20

Calculate a mask of historical dates in the given date range.
Use the mask to get the historical values for the date range.