Add values in rows if first values in consecutive rows match python

Question

I am working to reduce the rows in my dataframe based on the values in the first rows. If the value in the first column of a row matches the value in the second row of the first, I want to add the data in the residual columns.

My dataframe looks like this:

position	length	height
1	5.5	0.0
1	0.0	2.1
2	4.1	0.0
2	0.0	3.5

My desired output is this:

position	length	height
1	5.5	2.1
2	4.1	3.5

Answer 1

Try .groupby + .sum():

x = df.groupby("position", as_index=False).sum()
print(x)

Prints:

   position  length  height
0         1     5.5     2.1
1         2     4.1     3.5