How do I get the code to always select the latest file within a JSON file, then retrieve a specific value

Question

I don't want to change the code each quarter/year. How can I transform my function so it simply selects the latest file and retrieves a specific value - so in the example below, it would be the ['2020-12-31'] that is altered. Thank you

def freeCashFlow():
    for r in range(len(cleanstockdata2)):
        try:
            if (cleanstockdata2[r]['Financials']['Cash_Flow']['yearly']['2020-09-30']["freeCashFlow"]) in ['0','',None]:
                print (0)
            else:
                print (cleanstockdata2[r]['Financials']['Cash_Flow']['yearly']['2020-09-30']["freeCashFlow"])
        
         except KeyError:
             print (0)  

Answer 1

You can convert the values in the json to datetime objects and just take the max of them, for instance:

from datetime import datetime as dt
date_list = [dt.strptime(key, '%Y-%m-%d') for key in cleanstockdata2[r]['Financials']['Cash_Flow']['yearly'].keys()]
max_date = dt.strftime(max(date_list), '%Y-%m-%d')
desired_value = cleanstockdata2[r]['Financials'][max_date]["freeCashFlow"]