CODEWITHSUNDEEP
pythonpandasdataframe
Tharindu
Tharindu

Reputation: 311

Generate new column based on ratio of adjacent rows in pandas dataframe

I am quite new to pandas and I have a dataframe as follows,

  year  A    B
0 2000 101   20
1 2001 102   10
2 2002 103   5
3 2003 250   2
4 2004 500   4

I want to create new column ( column C) by dividing the column B row value by the row value just below it. As follows,

  year  A    B   C
0 2000 101   20  2 
1 2001 102   10  2
2 2002 103    5  2.5
3 2003 250    2  0.5
4 2004 500    4

Not sure how to do it ( think for loop helps), Thanks

Upvotes: 0

Views: 1624

Answers (1)

cs95
cs95

Reputation: 402824

Use div + shift:

df['C'] = df.B / df.B.shift(-1)    
df

   year    A   B    C
0  2000  101  20  2.0
1  2001  102  10  2.0
2  2002  103   5  2.5
3  2003  250   2  0.5
4  2004  500   4  NaN

Upvotes: 2

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