How to find average after sorting month column in python

Question

I have a challenge in front of me in python.

| Growth_rate  | Month |
| ------------ |-------|
|            0 |     1 | 
|           -2 |     1 | 
|          1.2 |     1 | 
|          0.3 |     2 | 
|         -0.1 |     2 | 
|            7 |     2 | 
|            9 |     3 | 
|          4.1 |     3 |

Now I want to average the growth rate according to the months in a new columns. Like 1st month the avg would be -0.26 and it should look like below table.

| Growth_rate | Month | Mean  |
| ----------- | ----- | ----- |
|           0 |     1 | -0.26 |
|          -2 |     1 | -0.26 |
|         1.2 |     1 | -0.26 |
|         0.3 |     2 |   2.2 |
|        -0.1 |     2 |   2.2 |
|           7 |     2 |   2.2 |
|           9 |     3 |   6.5 |
|         4.1 |     3 |   6.5 |

This will calculate the mean growth rate and put it into mean column.

Any help would be great.

Your question is quite vague, can you show us how you went from the original data to the ideal output data? — Aditya Diwakar, Jan 27 '19 at 17:42

score 2 · Answer 1 · answered Jan 27 '19 at 17:54

2

df.groupby(df.months).mean().reset_index().rename(columns={'Growth_Rate':'mean'}).merge(df,on='months')
Out[59]: 
   months      mean  Growth_Rate
0       1 -0.266667          0.0
1       1 -0.266667         -2.0
2       1 -0.266667          1.2
3       2  2.200000         -0.3
4       2  2.200000         -0.1
5       2  2.200000          7.0
6       3  6.550000          9.0
7       3  6.550000          4.1

answered Jan 27 '19 at 17:54

Onyambu

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Please check the image that i have attached – Parth Dhir Jan 27 '19 at 18:19
@ParthDhir what about the image? – Onyambu Jan 27 '19 at 18:22

kentwait · Answer 2 · 2019-01-27T18:15:34.773

0

Assuming that you are using the pandas package. If your table is in a DataFrame df

In [91]: means = df.groupby('Month').mean().reset_index()
In [92]: means.columns = ['Month', 'Mean']

Then join via merge

In [93]: pd.merge(df, means, how='outer', on='Month')
Out[93]:
   Growth_rate  Month      Mean
0          0.0      1 -0.266667
1         -2.0      1 -0.266667
2          1.2      1 -0.266667
3          0.3      2  2.400000
4         -0.1      2  2.400000
5          7.0      2  2.400000
6          9.0      3  6.550000
7          4.1      3  6.550000

edited Jan 27 '19 at 18:15

answered Jan 27 '19 at 17:50

kentwait

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I want mean of growth rate according to months. – Parth Dhir Jan 27 '19 at 18:10
@ParthDhir I think my solution does sort it by month as you showed in your example – kentwait Jan 27 '19 at 18:16
Please check the image which I have attached. – Parth Dhir Jan 27 '19 at 18:18

How to find average after sorting month column in python

2 Answers2