How do I create a an annualized growth rate for GDP column in my dataframe?-CodePudding

I basically want to apply this formula: ((New/Old)^4 - 1) * 100. To a data frame I have and create a new column called "Annualized Growth Rate" I have been working off of the FRED GDP data set.

I have a data set that looks something like this (not the real numbers)

Index	GDP
0	100
1	101
2	103
3	107

I want to add a column on the right that applies the formula I mentioned above so that the annualized growth rate numbers would start appearing in the index = 1 position

Index	GDP	Annualized_Growth_Rate
0	100	NaN
1	101	4.060
2	103	8.159
3	107	16.462

How can I go about doing this. I was originally trying to do it using iterrows() Something like

for index,row in iterrows():


   df['Annualized Growth Rate'] = df['GDP'].loc[index] / df.['GDP'].loc[index - 1]...

but then index position -1 is out of range.

I'm assuming there is an easy way to go about this that I just don't know. I also know you aren't really supposed to use something like iterrows. Any guidance would be appreciated.

CodePudding user response：

You can use shift to access the previous row and vectorial operations for subtraction, division, power, multiplication:

df['Annualized_Growth_Rate'] = df['GDP'].div(df['GDP'].shift()).pow(4).sub(1).mul(100)

Output:

   Index  GDP  Annualized_Growth_Rate
0      0  100                     NaN
1      1  101                4.060401
2      2  103                8.159184
3      3  107               16.462528