Quarter:    GDP:   GDP change:  change
1999q3     9           --         ------
1999q4    10           1          increase
2000q1     9          -1          decline
2000q2     8          -1          decline
2000q3     7          -1          decline
2000q4     6          -1          decline
2001q1     8           1          increase
2001q2     11          3          increase
2001q3     12          1          increase

Here is the Processed dataFrame Now I need separate list of all the quarters in which recession starts ,recession ends and bottom of recession

The start of recession in the example above is '2000q1'because the GDP decline started then

recession end is ''2001q2'

recession bottom is '2000q4' because it has the minimum GDP between start and end

You can use .loc attribute after setting the quarter the index of the dataframe.

Df.loc[start:end]

You can make the quarter the index of the dataframe using the following statement

Df = Df.set_index('quarter')

Hope that helps.

As asked by you how can you find the recession start and other parameters. Here is the code you can use:

for index in df.index:first_q = df.loc[index, 'gdp']second_q = df.loc[index+1, 'gdp']third_q = df.loc[index +2, 'gdp']

Now the logic is : (if second_q < first_q) and (third_q < second_q) then the first_q is the recession start.

And similarly if second_q > first_q and third_q > second_q then third_q is the recession end.

Basically recession start is the presence of 2 consecutive gdp decline years and recession end is the presence of two continuous GDP increase years