How can I fill a column based on a difference between the values of two different columns, using gro-CodePudding

I have the following data frame:

HorseId	FGrating	Max FGrating	Top
1736	110		No (no Max FGrating to compare with)
1736	124	110	Yes (FGrating - Max FGrating>=4)
1736	118	124	No (FGrating - Max FGrating <4)
13973	144		No (no Max FGrating to compare with)
13973	137	144	No (FGrating - Max FGrating <4)

The Top column is "Yes" or "1" when the difference between FGrating and MaxFGrating for that row is 4 or more.

I know I should use groupby, because I need this for each HorseId and perhaps the diff function, but I cannot put them together.

How can I do it?

CodePudding user response：

Your expected output is hard to make sense of, because the values in Top do not seem driven by any conditions in the table, except those two rows with MaxFGrating == -1 seem to be consistently MaxFGrating - FGrating.

>>> ((df['FGrating'] - df['Max FGrating']) >= 4).map({True:'Yes', False:'No'})
0    Yes
1    Yes
2     No
3    Yes
4     No
dtype: object

Or MaxFGrating - FGrating.

>>> ((df['Max FGrating'] - df['FGrating']) >= 4).map({True:'Yes', False:'No'})
0     No
1     No
2    Yes
3     No
4    Yes
dtype: object