Pandas: SettingWithCopyWarning: [duplicate]

Answer 1

The problem is in the code you have not shown us. Somewhere, you have done something like this:

df = other.loc[something]

That is the root cause of this error message. You need to assign using .loc or similar directly into the original DataFrame:

other.loc[something, 'DATE'] = whatever

Answer 2

You need add copy:

df = data.loc[data.ID == 79]

to:

df = data.loc[data.ID == 79].copy()

If you modify values in df later you will find that the modifications do not propagate back to the original data (data), and that Pandas does warning.